Tilapia Farming Guide - Part 1IntroductionAquaculture, specifically tilapia farming, comes in all sizes, from large commercial producers, to small backyard ponds. While they all share a few common ingredients, specifically water and tilapia, the equipment and methods used are different for each. It is unlikely, for example, that you would find an oxygen generator, cyclone filter, drum filter, or an ion exchange and electrochemical regeneration system for removing ammonia, on a back yard tilapia farm. Conversely, you probably wouldn't find any air stones, filter pads, or bio balls, in use at a commercial aquaculture facility. An important concept for you to keep in mind, as you make your way through this guide, is that no single method described is better than the other when it comes to your own farm. Just like shoe sizes, there is only one exact fit, everything else is either too big, or too small.In recent years there have been a few manufacturers who have developed "expandable" aquaculture and aquaponic systems for commercial use, but these are just small systems, using small farming methods, set up in repetition. These systems are not an economically viable alternative to purpose-built facilities, designed to exactly meet the desired production output from the very beginning. Additionally, there are a whole host of computerized controllers and testing equipment, that has been developed specifically for industrial sized aquaculture, and is now being marketed to backyard tilapia farmers. In smaller systems, with relatively low volumes of water, and rapidly changing chemistry, using pricey testing equipment may not deliver the expected benefits, resulting in farmers continually chasing down inexistent water "problems", and filets that cost a fortune to produce.We created this guide for anyone interested in tilapia farming. Wherever we describe a process, we will include methods for both large commercial production, and backyard tilapia ponds. We will use bullet points, the little red fish, to reiterate points that we think are important for you to remember. We'll also use green boxed text to add additional comments, that are either critical, or applicable to aquaponic growers. This guide will evolve as new methods are researched and then published in the Journal of Applied Aquaculture, or other reputable publications. We invite you to contact us about

anything that we haven't made perfectly clear, so that we can update this guide for the benefit of everyone. We wish you success.

Raising TilapiaFrom the tilapia farmer's perspective, there are three main events in the tilapia farming timeline: hatching, rearing, and harvesting. Of course, these events have many different names, depending on with whom you are talking. Some people might use words like spawning, grow-out, and processing, but no matter what terms they use, they're all talking about the same things. An important point to remember, is that we are referring to the events and jobs in the farming timeline, not the development cycle of the tilapia. Although they are interwoven, the tilapia are going through their own cycle of development that doesn't require any significant shifts in your responsibilities. Because this is an important distinction, we will briefly overview each of the tilapia farming events.

Hatching includes delicate jobs such as caring for breeding colonies, encouraging or inducing spawning, egg extraction or nursery isolation, tilapia fry care, and ultimately raising the fry to fingerling size. Each of these jobs has several individual steps and techniques that are unique to the operation of a tilapia hatchery. It should also be noted that the equipment and facilities used for hatching, are unique to hatchery operations, and only useful during the first few weeks of the tilapia’s life.

Rearing is the part of tilapia farming that picks up after the hatchery has raised them to fingerling size. At this stage, the tilapia farmer's goal is to raise the tilapia to harvest size quickly, economically, and in good health. Tasks include testing, sorting, weighing, and several maintenance jobs. These tasks are the subject of this guide.

Harvesting involves selecting tilapia, moving them to a finishing pond, killing them humanely in a way that respects what they are providing, and then removing their filets. Many of these jobs can be skipped by the farmer and passed on to the person preparing the tilapia. The equipment used for harvesting has nothing to do with the rearing facilities, and obviously doesn’t incorporate any of the hatchery equipment.

So as you can see, hatching, rearing, and harvesting not only involve completely different sets of responsibilities, they also require different equipment and facilities. It should also be noted that the size of the operation doesn’t matter. For example, a processing facility can be as complex as climate controlled clean room, full of stainless steel tables and equipment, or as simple as a home kitchen, with a sink and a cutting board. Every tilapia needs the same things to live, and the only difference between the large commercial farm, and the backyard farm, are the methods used. In the end, the results are all that matter. The level of creativity that you use to get there is up to you, and part of the personal satisfaction that you'll get from tilapia farming.What follows is intended to be a need-to-know, answers-only guide, to tilapia farming. We're not going to fill your head with theory and science beyond what is absolutely necessary. In addition, we are going presume that you have an average level of common sense. With respect to book writers, who have to fill pages with text by stating, and then repeating, the obvious, sentences such as "the tilapia go into the pond", are not a part of this guide. So without further ado, let's learn about tilapia farming.

The Five Needs Of TilapiaTilapia don't ask for much. In fact, they only have five basic needs: clean water, oxygen, food, light and room to swim. Give your tilapia these things, and they will stay healthy and grow fast. The art of tilapia farming is to understand each of these needs, and then find a way to provide them in sufficient quantities. The problem is, that each of these five needs comes with a myriad of potentially

complicated questions, and solutions. In the next five sections, we will address each of the tilapias needs, one at a time.Aquaponics Point: Tilapia do not care what you do with their poop, or how you remedy ammonia and nitrate contaminated water. It does not matter whether your operation is straight aquaculture, or you use your tilapia's pond water to grow plants. Aquaponics is not a new way to raise tilapia; it is an alternative way to deal with, and benefit from, fish waste. Of course, if you were to ask vegetable farmer, they might tell you that aquaponics is a novel way to fertilize their plants. However, regardless of your perspective, in all farming situations, the needs of the tilapia remain the same.

1. Clean WaterProviding your tilapia with clean water can be split into two parts: new water introduction and existing water maintenance.

New Water IntroductionWhenever you introduce new water into your pond or aquarium, it needs to be of the same quality that you would drink yourself. In fact, if you aren’t willing to drink the water that you are introducing to your tilapia, then you need to stop giving it to them until you are. Tilapia are a food fish, so whatever is in their water, will eventually wind up in your body. You might as well drink the water now, and cut out the middle-fish. Your water should only come from a safe municipal source, or a clean private well. If you only buy bottled water, because you can’t stand the taste of your own local water, then do something about it. Buy a filter, a softener, a nitrate remover, or a high volume reverse osmosis system, and do whatever it takes to get the water to a condition that you will drink.After you are happy with the drinkability of your water, fill up a food safe transfer container, or tank, to further treat the water before you give it to your tilapia. Don’t ever just run a hose from the water source directly to your pond. Sudden changes in temperature, pH, or other water chemistry coming through the hose are common. This can stress tilapia, causing weakened immune systems, and could even upset the balance of biological filtration. The size of the transfer container is up to you, but we recommend that it be able to

hold at least 20 percent of the volume of your pond. For commercial operations, 100 percent is recommended.As you are filling your transfer container(s), you need to make sure that the water you are going to add to your tilapia pond is at the same temperature as the water to which they are already accustomed. Plus or minus a couple of degrees is okay, but if the difference is too great, it could shock them, and weaken their immune systems.

Make sure that you are willing to drink from your water source before you give it to your tilapia.

Put new water into a transfer container, for further treatment, before adding it to your pond.

Make sure that the temperature is the same as to what your tilapia are already accustomed.

In addition to making sure that the newly introduced water is clean enough for you to drink, and at the right temperature, you need to make sure that the water is free of all chemicals added by the municipal water authority, especially chlorine. A gallon jug of DeChlor goes a long way, when you consider that you only add one drop per gallon of water, to remove chlorine, and reduce the toxicity of heavy metals like copper, cadmium, mercury, silver, zinc, lead, nickel, manganese, and sodium selenate, which can be present in any water supply. Also, do not assume that chlorinated municipal water will lose its chlorine content on its own, over time. This is especially true for indoor ponds. Even if you can't smell the fumes, it only takes trace amounts to cause deadly chemical burns to their gills, and throughout their bodies.

Use DeChlor to remove chlorine and reduce heavy metals in new water, before it is introduced into your tilapia pond.

Do not rely on time to remove chlorine from your water.You also need to make sure that newly introduced water is at the ideal pH level, and that it is at the same pH level of the water already in your pond. This may seem like a strange way of saying it,

but the wording is intentional. Fish keepers tend to get into a bad habit of adjusting the pH level of their ponds to ideal, by introducing new water with a significantly higher or lower pH. Their hope is, that when the new water is added to the old water, the different pH levels will mix, and result in the target pH. This is the equivalent of throwing sulfuric acid and baking soda at someone, in the hopes that the two will cancel each other out, and achieve some perfect balance.The proper procedure, is to test the pH level of the water in your pond, and use pH-Down, or pH-Up, to bring the existing water to the ideal level slowly. At the same time, adjust the water in your transfer container(s) to the same ideal pH level. Be sure to read the labels of all of the products or chemicals that you want to use, to make sure that they do not read “not intended for food fish” on the warning label. Once the new and existing waters are at exactly the same pH (and temperature) level you can move on to the next treatment step, or safely drain off the existing water and introduce the new water to your tilapia.So the obvious question is: What is the ideal pH level for tilapia? The easy answer is 8.0, but there are some common situations that make 8.0 impossible. Plants, in an aquaponic system, prefer a pH closer to 7.0, and since the fish and plants share the same water, a pH level of 6 or 7 (point) something becomes the ideal. We’ve seen some ponds that rapidly creep to about 8.4, and stay there, no matter how many times the water is treated back down to 8.0. In those cases, we stop fighting the losing battle, and just make 8.4 the new ideal. It is far better to let the fish swim in a pH of 8.4, than it is to constantly hit them with pH changes.Critical Point: The extreme pH ranges for tilapia are between 3.7 and 11, and the pH ranges for optimal growth are between 7 and 9. However, a more toxic form of ammonia, known as un-ionized ammonia (NH3), is produced in water with a higher pH (and temperature) level. The other variety, ionized ammonium (NH4

+), is not toxic. The pH of water changes with alkalinity, and also fluctuates with carbon dioxide levels, which rise and fall with photosyntheses. We therefore recommend that you keep your pond between 6.5 and 8.0 to mitigate potential losses due to a spike in ammonia. Also, because pH and Ammonia are cyclic, we

recommend that you only test pH and Ammonia in the late afternoon.

Adjust the pH of the water in your transfer container and your pond to ideal before you introduce the new water to your tilapia.

Finally, you should match the salinity of newly introduced water to the existing pond water. Many tilapia farmers add a small amount of non-iodized salt (NaCl) to their water, to aid in the prevention of parasites, and to mitigate the problems associated with elevated nitrites (Brown Blood disease). Adding salt to a measurement of 6 parts per thousand, or to a specific gravity of 1.004, which is roughly one tablespoon of salt per gallon of water, will prevent most parasites from developing. Of course, for every level of salinity, there are parasites that can thrive, but the purely fresh water parasites seem to develop the earliest.While we're on the subject of salt, some old-timers might tell you that sodium bicarbonate (NaHCO3) or epsom salt (Magnesium sulfate, MgSO4) can, or should be used instead of common table salt (NaCl), but this is incorrect. Sodium bicarbonate is used as a temporary buffer for fish hauling and shipping purposes, and epsom salt has limited uses in aquaponic systems, and is of no use to fish farming operations.Critical Point: You can safely add salt (NaCl) up to 36 parts per thousand for Blue and Mozambique tilapia, however the recommended maximum for optimal growth is 19 parts per thousand. Nile tilapia are not as tolerant to saline water. Nile tilapia should not be put in water containing salt levels above 18 parts per thousand.

If necessary, match the salinity of any new water to your pond before giving it to your tilapia.

Aquaponics Point: While aquaponics can significantly decrease the frequency of traditional water changes, or eliminate them entirely, the action of adding water lost to evapotranspiration (look it up) is effectively a water change in itself. Fresh, clean water contains many trace minerals that are beneficial to both the tilapia and to the

plants. Use a good nitrate test kit periodically, just to be sure that your plants are keeping up with your fish. Also, since we mentioned epsom salt above, never add more than three parts per thousand of epsom salt to your aquaponic system.

Existing Water MaintenanceThe water that your tilapia are swimming in, will never be cleaner than when you first introduce it into their pond. From that point forward, your pond water will continue to get more and more toxic, until it kills your tilapia, unless you intervene by removing the old dirty water, and introducing new clean water into their pond. Most people are surprised to learn that many fish farms, particularly trout and salmon farms, use no filtration or treatment whatsoever, and instead, rely on constant water changes. This is normally accomplished by diverting water from a nearby river, through the fish ponds, and back out again in a continual flow. Another method, is to do away with the pond altogether, and just raise fish in large suspended nets, out in the middle of a lake, or slow moving river. In fact, you can even raise tilapia in an aquarium, at home, without any filtration or treatment at all, provided that you are willing to replace their water every single day. But honestly, who has that much free time?

Tilapia do not need filtration to thrive as long as you are willing to replace their water every day.

For those of us who don’t want to do daily water changes, there are ways to delay the task for days, weeks, or even months, by using filtration and treatment. In fact, the only purpose of filtration and treatment is to buy yourself some time between water changes. How much time you get, depends entirely on how efficient the filtration, or how effective the treatment is. For the rest of this section, we will go over some of the common things that make tilapia pond water toxic, and what you can do to delay, or prevent, their build up; so that you can reduce the frequency of water changes.

Filtration and treatment are used to convert or reduce toxic compounds in aquaculture water, thereby reducing the frequency of water changes.

Undissolved solids are the first things that will begin to make your tilapia pond water toxic. This is the stuff that you can easily see, suspended in the water, or resting on the bottom. Basically, it’s uneaten food and tilapia poop. These solids will eventually dissolve into the water, becoming dissolved solids, and will contribute to the build up of toxic compounds, such as un-ionized ammonia. The best way to trap these undissolved solids is to start with a solids separator. Every good filtration system incorporates some form of barrier-less solids trap as its first step. This is normally followed up with a pre-filter that passes the water through a barrier material. Disposable or serviceable filter pads are typically used for this purpose. If applied correctly, this two step approach will capture nearly all of the undissolved solids in your system.It's important to note that solids separators and pre-filters do not remove solids, they trap them. Until the solids are actually removed, they will continue to contribute to the toxicity of your pond water. Normally, a solids separator has some sort of manual or automatic flush valve, that needs to by cycled on a regular basis. And, depending on how much of the solid waste gets past the separator, the pre-filter material will need to be replaced or serviced too.

Undissolved solids are trapped by solids separators and pre-filters, they are not removed.

Undissolved solids, stored in separators and pre-filters, contribute to pond toxicity (un-ionized ammonia) until they are removed.

Dissolved solids are comprised of food and poop, which has been broken down into very fine particles, that remain suspended in water, and pass right through solids separators and pre-filters. Dissolved solids contribute to the formation of other, more toxic compounds, such as un-ionized ammonia. The best way to trap dissolved solids, for most aquaculture, is with the use of a fine-

particle barrier filter. On very large fish farms, where the volume of water is closer to that of a small city, chemical processes may be used to remove dissolved solids, as part of a separate water treatment and reclamation system. Like solids separators and pre-filters, fine-particle barrier filters do not remove dissolved solids by themselves. You must service the filter to remove the contaminants. We will refer to this filtration step as "fine-particle" throughout this guide.There are other dissolved contaminants, such as tannins and phenols, which can color your pond water to look like tea, and make it smell bad. These contaminants are caused by decomposing organic matter, and are so small that they pass right through fine-particle barrier filters with ease. The only way to remove these, nearly microscopic particles, is with activated carbon, or with chemical treatment typically used on larger farms. Unfortunately activated carbon is exhausted very quickly, and can be relatively expensive to replace, so it's not practical for constant use. Our opinion is that activated carbon should be only used on an as-needed basis, on smaller tilapia farming operations, to clarify tea colored water, or reduce odors. Activated carbon is not an economically viable solution for commercial tilapia farming use.

Fine-particle filters only trap dissolved solids, they do not remove them. You must clean your filter media to stop the dissolved solids from making your pond toxic (with ammonia).

Activated carbon is useless against dissolved solids, but can be used to trap tannins and phenols in smaller ponds.

Un-Ionized Ammonia is the first truly deadly compound that you will encounter. Un-ionized ammonia is produced by decomposing organic matter, and excreted by tilapia via their gills, in water with a pH above 7.0. The only way to remove un-ionized ammonia, is to replace the water, or find a way to eliminate the ammonia. The good news is, there are naturally occurring bacteria that readily consume ammonia. The bad news is, the ammonia-eating bacteria (Nitrosomonas) give off even deadlier compounds, called nitrites. Nitrites oxidize hemoglobin into methemoglobin making it difficult for your tilapia’s blood to carry oxygen (hypoxia), and will

cause suffocation at the slightest exertion. Fortunately for the tilapia, the nitrites are further oxidized into something far less lethal, called nitrates. Once nitrites have been converted into nitrates, your tilapia are out of immediate danger. Over time, however, the nitrates will build up in your pond, and you will finally have to do the dreaded water change.Critical Point: Test kits and equipment only read the "total ammonia", but this has nothing to do with the level of toxic (NH3) ammonia present in the water. The level of toxic ammonia must be calculated in conjunction with the pH level and temperature. At room temperature with a pH of 6.0, all of the ammonia is basically non-toxic. At a pH of 8.0, only about 10 percent or less is toxic. In fact, you have to raise your pH to 9.0 before the total ammonia is only half-toxic. What's the hidden lesson in all this? You can control the toxicity of ammonia using pH!

For the rest of this guide, the reader should consider all references to ammonia to mean toxic un-ionized ammonia, unless otherwise specified.

Another Critical Point: Ammonia is toxic to Blue tilapia at concentrations above 2.5 milligrams per liter, and above 7.1 mg/L for Nile tilapia. However, ammonia concentrations as low as 0.1 mg/L will depress food intake and growth. Always strive to remove toxic ammonia completely from your system. Even small amounts can cost money in the form of longer grow out periods and wasted food.The nitrifying bacteria (Nitrobacter), responsible for converting ammonia into nitrite, and then into nitrate, live on every surface of your pond. Some of these bacteria are aerobic, meaning that they need oxygen, and some are anaerobic, which means that they grow in conditions with very little oxygen. Normally, you will find aerobic and anaerobic bacteria along the water line in your pond, on under water surfaces and inside pipes. Unfortunately, that's not nearly enough surface area, to support the number of bacteria colonies needed to convert the amount of ammonia being produced. The solution, is a contraption commonly referred to as a bio filter or bio reactor.

Bio filters only have one purpose: to give a whole lot of surface area for nitrifying bacteria to grow on. Some bio filters are designed to support primarily anaerobic bacteria, while others are capable of supporting both aerobic and anaerobic bacteria. The two most popular bio filter medias are bio sponges and bio balls. Bio sponges are for supporting under water, primarily anaerobic bacteria while bio balls can be used for above water (primarily aerobic) or under water (primarily anaerobic). Other good bio medias include stranded PVC and bio straws. Unlike the filters designed to trap undissolved and dissolved solids, the bio media should not be serviced until the water flowing through is being restricted. Even then, they just need a light rinsing to get the water passing through them again.Aquaponics Point: Your grow bed is your bio filter, unless you are only using floating rafts. In aquaponic systems that only use floating rafts, we recommend that you incorporate a bio filter somewhere in your plumbing. For example, after your solids separator or between your sump and fish tank.

The bio filter only provides a growing surface area for the nitrifying bacteria that eliminate toxic ammonia.

Never clean or sanitize your bio filter, just rinse it lightly if it is restricting the flow of water.

It should also be noted, that there are recently developed technologies, for commercial aquaculture, that convert toxic ammonia into harmless nitrogen gas. In the near future, there will no longer be a need for anyone to give a second thought to nitrifying bacteria, or bio filters. Currently, these technologies are out of economic reach for the average tilapia farmer, but change is on the horizon, and it's only a matter of time before someone makes a unit that anyone can afford.The final step in providing your tilapia with clean water, has to do with the prevention of parasites and pathogens. If you don’t take measures to prevent them, parasites will probably happen to your tilapia at some point. As we mentioned earlier on this page, if you get caught with parasites, you can kill them pretty easily, without hurting your tilapia, or ruining their food value, by changing the salinity of the water to 6 parts per thousand, using non-iodized salt.

This will wipe out the parasites very quickly. It should also be mentioned that, if you are raising your tilapia in water that already contains salt, and they get a parasitic outbreak, you can put your tilapia in fresh water to kill the parasites. In a nutshell, parasites can’t handle sudden changes in salinity.If your tilapia get a pathogen (disease) however, it’s game over. Euthanize your tilapia, drain your pond, disassemble your filtration, and sanitize the expensive parts with bleach, throwing away everything else. No, we’re not kidding. It is illegal in the United States to sell a food fish that has been treated for any disease, and for good reasons. Many pathogens are untreatable, and those that are treatable, require expensive injections, that cost more than the tilapia themselves, and must be administered individually. Not to mention the fact that the incubation period for most pathogens, is longer than it takes for the tilapia to grow to harvest size. So it would never be clear if they still had the disease during harvesting and processing. Pathogens are all-around bad news in tilapia farming.Remember from high school biology class, that parasites are the nearly microscopic living organisms that feed on your tilapia, and pathogens are the actual diseases. For our purposes, we'll lump viruses in with parasites, to keep the discussion simple, even though they infect tilapia in completely different ways. When is comes to parasites and pathogens, it is more practical to concentrate your efforts on prevention, rather than reacting to an outbreak. The first step in prevention, is to reduce the risk of getting them in the first place. The following is a list of preventative measures that we suggest:

Sanitize your hands and arms before putting them into your pond water.

Use gloves. Maintain clean conditions around ponds. Sanitize the floors of

indoor areas, and sanitize the bottoms of shoes if practical.

Keep separate sets of equipment, such as nets and buckets, for each pond.

Adopt a colored bucket system. White for clean water and fish holding, blue for equipment and filter cleaning or carrying, and gray for toxic water carrying.

Avoid conditions that cause weakened immune systems in tilapia, such as stress due to overcrowding, poor nutrition, and high levels of nitrates.

Prevent pets, and other animals, from drinking from your tilapia pond water.

Keep birds from pooping in your tilapia pond. Do not put snails, shrimp, goldfish, or any other living

organisms, in your tilapia pond water.Critical Point: Never ever put tilapia in a system that has been occupied by snails or goldfish. The guy who tells you different only won his last turn at Russian Roulette. Snails and Goldfish carry parasites that are foreign to tilapia and will kill them. You may get away with it a few times, but eventually the odds will catch up with you. It goes without saying, never buy your livestock from a hatchery that offers snails or goldfish either. Once these parasites have found refuge in your system, it will need to be completely sanitized to remove them.An ultraviolet sterilizer is the single best piece of equipment that you can use to control parasites and pathogens in your pond water, before they can get into your tilapia. By passing water in close proximity to an ultraviolet light source, a UV sterilizer kills the most common tilapia parasites. The key to successfully sterilizing your pond, is to expose the right volume of water to the UV light source, for the correct amount of time. In the case of ultraviolet sterilizers, bigger and more wattage is not necessarily better. It is important to select one that is the correct size for your pond, and then make sure that you adjust your plumbing to the manufacturers recommended

water flow rate. You can time how long it takes for the water coming out of your UV sterilizer to fill a five gallon bucket, to determine the flow rate, and then adjust it with a ball valve in front of the inlet if necessary.

Parasites can be eliminated from your tilapia and your water with salinity changes.

An ultraviolet sterilizer can only remove parasites and pathogens from water, not from the tilapia themselves.

Eliminating parasites and pathogens in water will prevent them from transferring between individual tilapia.

Individual tilapia with parasites can be treated by placing them in a tank of water containing 6 ppt of non-iodized salt for a few hours.

Pathogens in tilapia cannot be treated effectively, economically, and in some cases legally. The only viable answer is prevention.

There are a couple more things that are worth mentioning about ultraviolet sterilizers. First, they are the only realistic option for preventing parasites in aquaponic systems. Some aquaponic dealers pretend that diseases don’t happen, but this has more to do with salesmanship than anything else. After all, a car salesman doesn’t show pictures of people injured in car accidents as part of his advertising, so it’s understandable. But tilapia in aquaponic systems do occasionally get sick, and a UV sterilizer won’t adversely affect plants like salt can. The second point worth mentioning, is the fact that Ultraviolet sterilizers also kill phytoplankton, the stuff that turns your water green.So there you have it. The answer to the question of what constitutes clean water, and what can be done to keep it that way. But we're not quite finished with water yet. We still have to go over heating and filtration systems in general.

Filtration ComponentsSolids Separators: The most common type of barrier-less solids separator in aquaculture makes use of a phenomenon known as the "Tea Leaf Paradox". It was introduced by Albert Einstein, so don't feel dumb if you've never heard of it, or don't fully understand how it works. Basically, when you spin water in a bucket, the pressure of the water at the outside edge is greater than it is in the center. However, where the water touches the sides and bottom of the bucket, friction slows it down and the pressure drops. Since the water touching the sides and bottom can't keep pace with the rest of the water in the bucket, a boundary layer is formed. The water on the outside of the boundary layer takes a different path downward, towards even greater friction at the bottom. This secondary flow of water, aided by the pressure gradient of the spinning water, sweeps undissolved solids into a neat pile in the center of the bucket.Separators that work on this principle are commonly referred to as swirl traps, or swirl filters. In commercial aquaculture, these are normally constructed using cone-bottom tanks. On a smaller scale, these can be constructed from 25 gallon tubs. Another type of solids separator is known as a settling tank. There are several variations on this theme, but basically it's just a barrel through which water is passed, and anything that is heavy enough, sinks to the bottom. The problem with settling tanks is that they are harder to clean, and can only trap sinking solids. The final type of solids separator worth mentioning, is called a centrifugal separator. These separators work by spinning the heavier particles into a collection chamber where they can be flushed. These types of separators are only useful for removing the heaviest solids.There is a good test that you can do, to determine what kind of separator you need. Simply fill a clear jar with the dirty water that you want to clean. Make sure to add some of the solids that you want to separate, and put the lid on the jar. Shake the jar for a few seconds and then set it down, undisturbed, and watch what the particles do. If all of your solids sink to the bottom within three minutes, you can use a centrifugal separator. If all of the solids sink to the bottom in ten minutes or less, you can use a settling tank. However, if some of the particles sink, and others float, and some even hover in the middle, you will need to use a swirl trap.

Pre-Filters: A pre-filter is nothing more than a barrier that traps undissolved solids as water passes through. If you are using a swirl trap, then the pre-filter will serve as a secondary trap for solids that have a neutral buoyancy, or otherwise escape. If you aren't using a swirl trap, then your pre-filter must be designed to handle a large amount of solid material. Drum filters are the most common types of pre-filters found on medium and large tilapia farms. Some drum filters are the size of city busses, while others are not much bigger than a recliner; it all depends on the amount of solid material being produced by the tilapia. Don’t be afraid to use your own ingenuity when it comes to pre-filters. There is nothing magical about commercially produced filtration systems. If you have the skills to make your own, by all means go for it. A good analog for a pre-filter is nothing more than a bucket, with holes drilled in the bottom, filled with polyester pillow stuffing, suspended over the pond, and a pump to drop water through it. Of course, this isn’t very practical, because it would be time consuming to service, and there are other filtration steps that need to happen, but the analogy is still accurate.Aquaponics Point: You are running an aquaponics system to grow vegetables, not a fish sewage treatment plant. Do not allow any solid wastes to enter your grow beds. Always use a settling tank or swirl filter to remove as many undissolved solid particles as you can, before they make it to your plants.Fine-particle filters: Use a bead filter, sand filter, diatomaceous earth filter, or in-line water filter right after your pump, to trap dissolved solids. They are very effective at removing the particles that are too small to be trapped by any other filtration step. On a small scale, fine-particle filtration might not be necessary, due to the relatively low volume of water. This is especially true if you set up a pre-filter consisting of a swirl trap, followed by some compressed polyester pads. The biggest worry with this configuration will be an increased level of tannins and possibly phenols. In commercial tilapia farming, fine-particle filters are fitted between the water pump and the final water sterilization and polishing.Biological filter: Not really a filter at all, its only purpose is to provide a large surface area on which nitrifying bacteria can grow. A box, with water in the bottom, and some bio media, provides plenty of surface area for bacteria colonies to develop. If you want, you can

put some bio media above the water to allow aerobic nitrifying bacteria to take hold. There are a few design tricks to keeping a constant water level inside a plastic box, but it’s nothing that you can’t figure out if you decided to make your own. Biological filters should not need much servicing. In fact, you should avoid messing with them at all unless you notice that they are restricting the flow of water. This is why we prefer the wet/dry system, as opposed to the sand filters - the clear plastic makes it easy for us to see what is happening inside the bio filter.Aquaponics Point: Flood and drain grow beds are the biological filter in aquaponics systems. In systems consisting of only floating rafts, a traditional biological filter will still be needed. There, we said it twice.Ultraviolet sterilizer: This is not something that you should try to make yourself. Not because you might electrocute yourself, but because it probably won’t work. With UV sterilizers, the flow has to be just right. If it’s too fast, the parasites and algae will just fly right past the ultraviolet radiation and not even be affected by it, if the flow is too slow, it won’t kill them at a fast enough rate to keep up with their reproduction in your system. An ultraviolet sterilizer can also reduce the beneficial bacteria suspended in your water, so we don't recommend that you add a UV sterilizer until after your biological filter is established. Make sure to get one that is easy to clean. The clear tube separating the light from the water, also known as a quartz, needs cleaning from time to time. Some models come with a wiper system to do the job.Be sure to understand that an ultraviolet sterilizer cannot cure any disease, or remove any parasites, or viruses, that are already on, or in, your tilapia. The only thing that a UV sterilizer does, is kill the organisms that are suspended in the water. It can be compared to putting a HEPA filter in a room with a sick person. It won’t do anything to cure the sick person, but it might help others from getting sick. That said; there is a difficult to understand benefit of ultraviolet sterilization known as “Redox” that happens at the molecular level, and greatly contributes to the immune systems of tilapia, and their ability to resist diseases. We promised to limit the science, so we'll let you look up "redox potential" on your own.

A UV sterilizer can not cure sick tilapia; it can only reduce the spread of disease.

A UV sterilizer will kill free-floating single cell algae in your system. This type of algae is not beneficial to fish or plants, and can be dangerous due to its affect on carbon dioxide and pH levels.

A UV sterilizer contributes to the “Redox” potential of your pond water, which greatly enhances the tilapias immune systems and their resistance to disease.

Water heating: Heating pond water during the cold months is the bane of every tilapia farmer. Factors such as incorrect species selection, and improper pond construction, can force tilapia farmers to spend all of their profits, or negate all of their savings, just to keep their tilapia alive in the winter. Death by cold water is the number one service call that we get in our area between January and March. If you’ve read elsewhere on our website, you already know how important selecting the right tilapia species is, but just as important, is proper pond construction. Tilapia ponds should be separated from the ground by some margin of insulation. Even if it's only an inch of foam, it's better than having the cold ground act as a heat sink for your pond water. Insulating the sides of your pond, and covering the top with rigid foam at night, will help contribute to lowered heating costs. In colder climates, or places where electric heat is not available, or desired, a green house with a rocket stove may be the only solution.When it comes to heating your pond water, you have two basic options: The direct heating method and the heat exchanger method. To use the direct heating method, simply put one or more heating elements into the water flow of your pond. Heating elements can be metal probe type, aquarium type, or even simple water heater elements. Just use whichever one fits your system, and budget, the best. With electric heaters, don’t get yourself hung up on individual wattage. Two 300 watt heaters do the same work, and use the same electricity, as one 600 watt heater and so on. It might be more cost

effective for you to buy several smaller heaters, instead of one big unit.The second method of pond heating, is to use an external heat source, and transfer that heat into the pond, using a heat exchanger. A heat exchanger can be made using a series of CPVC pipes, running back and forth, covering the bottom of your pond or sump. Heated water is then pumped through the submerged pipes, warming the surrounding water. The source of heat can be a small water heater, more heating elements, or even a solar water heater. Our favorite method to heat the exchanger, is to use a small water heater, with a circulation pump, and a small pressure tank. A bright LED digital thermometer is also helpful. You might even install a low temperature thermal switch, to shut the circulation pump off, when the pond reaches a certain temperature. If you decide to try a solar water heating method, be sure to have an electric back up, just in case you get too many overcast days in a row.So that’s it for clean water let's move on to the second thing that tilapia need.

2. OxygenCritical Point: In this section, we will try to explain, in just a few paragraphs, what would normally take a college course to understand. Our original statement, that this is an answers-only guide, is especially true for this section. The conclusions that we present here, come from university studies, and well-respected international research institutes. If you want more information, we highly suggest that you start your research at the Food and Agriculture Organization of the United Nations, and then follow up with university research papers.The air that you breathe is a mix of gasses, consisting of 20.95 percent oxygen (O2), and 78.09 percent nitrogen (N2). The remaining .93 percent is made up of other gasses (Ar, CO2, Ne, He, CH4, Kr, H2 and Xe). Most people know that water is made up of hydrogen and oxygen (H2O), so they assume that fish get their oxygen from the water molecules themselves. However, a fish's gills do not have the capability of separating the molecular bonds of water, so the oxygen in an H2O molecule is unavailable for respiration.

Surprisingly, the oxygen that fish breathe, is the exact same oxygen gas that you breathe. On land, your oxygen is delivered to your lungs "suspended" in an inert nitrogen gas; under the water, a fish's oxygen is delivered to their gills suspended in a hydrogen/oxygen liquid. It is mixed in with the water on a molecular scale. You would no sooner see the oxygen in the water, than you would the oxygen contained in the air that you breathe. This is called dissolved oxygen. Don't confuse dissolved oxygen with bubbles of any size, even the smallest bubble is millions of times larger than the oxygen molecules that fish use for respiration.Since the oxygen, that is dissolved in water, is the exact same oxygen that is "dissolved" in the air, it would be logical to assume that oxygen can travel freely between air and water. Unless of course, we're talking about a calm body of water. Because you see, on a calm body of water, such as a pond, the water molecules near the surface act differently than the rest. Because they don't have any H2O molecules above them, to exert any attractive force, the top few layers of water molecules line up, and form stronger bonds with each other. This force is known as the surface tension layer, and it dramatically slows the transfer of oxygen entering, and waste gases escaping, the water. An easy way to visualize the surface tension layer, is as a big sheet of plastic wrap, on top of the water, suffocating everything underneath.On a moving body of water, such as a river, there is no surface tension layer. The constant churning of the water, continually drives the top molecules downward, breaking their bonds to each other. Without the surface tension layer, oxygen molecules can freely travel between the air and the water without any effort. Fortunately, for life in ponds, there are other forces can drive the top layer of molecules apart, punching holes in the the surface tension layer, and allowing for the free travel of oxygen and other gases. Strong wind or rain, for example, does a great job of breaking the surface tension. Also, bubbles, bursting at the surface, open holes in the top layer that allow for the exchange of gases.The surface tension layer does more than just keep oxygen from entering the water freely, it also slows carbon dioxide and other gases from escaping. In tilapia ponds, carbon dioxide molecules are the by-product of fish respiration and organic decomposition. Carbon dioxide must be allowed to escape, or the pond will stagnate

and the oxygen-dependent life, will not thrive. Fortunately, the same actions that allow oxygen to enter the water, also allow carbon dioxide to escape. This is commonly referred to as the gas exchange. For tilapia farming operations, breaking the surface tension, to allow for an exchange of gases, is a requirement, not an option. It is the only way that carbon dioxide can escape freely, and one of only two viable ways that oxygen can enter the water at an adequate rate.As in all things tilapia farming, the method used to break the surface tension, known as surface aeration, is an economic decision. There are just as many ways to accomplish the task, as there are ways to share your money with retailers and manufacturers. Some methods allow for a high volume of gas exchange, but come at an unreasonably high purchase price, and require a lot of energy to operate. Others are very cheap to operate, but do very little to facilitate an effective level of gas exchange. The effectiveness of any surface aeration method can be expressed as a ratio of the energy consumed to the surface area affected. The following methods, offer the best ratio of surface agitation to power consumption:

Cascades, waterfalls, and fountains are very cheap to operate, and can be set up to break the surface tension over a very large area. To keep this method cost effective, do not restrict the water flow, or lift the water very high above the surface. The water can be dropped down, or jetted up, either direction is effective.

Aggressive bubbling, that causes the water to be lifted, one inch or more above the surface. Use an air pump that can deliver more than 3 cubic feet of air per minute, at a minimum pressure of 6 pounds psi, and a 2x2 inch coarse air stone. Do not waste energy trying to pump air through a fine air stone, such as a ceramic diffuser, this is the wrong application for fine

bubbles. An efficient pump for this method will cost less than 2 dollars per month to operate.

Paddle wheel aerators. For large ponds, the paddle wheel aerator offers the lowest energy cost, for the amount of surface area affected.

Critical Point: Don't get hooked in by marketing claims. Surface aeration is a multimillion dollar industry full of expertly crafted conjecture, that sounds reasonable to air-breathing humans. Any method to break the surface tension must be measured as a ratio of the energy used, to the surface area affected.Tilapia need water with a dissolved oxygen content above three parts per million. In a pond with a biomass of one pound for every 3.74 gallons of water, surface aeration will normally keep the dissolved oxygen level within a healthy range; even at 4:00 a.m. when the Diurnal change in dissolved oxygen concentrations are at their lowest. However, we recommend that a minimum oxygen density of 4 ppm be measured once in the early morning (before sunrise), and then during the season at the warmest water temperatures. After it is confirmed that the dissolved oxygen content is above 4 ppm at these times, a routine daily monitoring can be made, in the late afternoon. The daily late-afternoon monitoring will be different from the reading taken at other times and temperatures. However, as long as it is performed at the same time each day, it will provide a good benchmark to know when to take more sunrise, or high-temperature readings; or to determine the need for supplemental oxygen.Egghead Point: Sorry for dropping that Diurnal bomb on you in the paragraph above. It's just a fancy way of saying daily. But, we used the word diurnal to make the point that the science of dissolved oxygen is complex. Take the following formula for example: O2¢ ¢ - O2¢ = P - R - Y ± A where P = the oxygen produced via photosynthesis, R = the respiration of all living organisms in the pond including bacteria and plants, Y = the quantity of oxygen stuck in the sludge or mud at the pond bottom, and A = the amount of oxygen dissolved from, or released to, the atmosphere.

It's actually a simple formula for expressing the changes of dissolved oxygen over a period of time, expressed as t¢ ¢ - t¢. There are however, no shortage of very long and complex formulas for expressing the physics of oxygen in water.So far we have limited the discussion to surface aeration methods. This is because surface aeration is all that is needed in recirculating aquaculture systems, with a biomass of 2 pounds per cubic foot, which can also be expressed as one pound per 3.74 gallons. It should also be mentioned, that certain non-recirculating systems, such as tilapia farming operations that divert river water, may also use surface aeration, in the form of a series of waterfalls, before the water is utilized. If the tilapia farming is being done in nets, suspended at the surface of a large body of water, such as a lake or very wide river, no surface aeration is normally necessary. However, if the suspended nets are floating in smaller bodies of water, such as ponds, surface aeration is still recommended.

Water temperature influences oxygen contentTo illustrate how the water temperature can affect the amount of oxygen that the water contains, here's a practical comparison: At one standard atmosphere (760 torr), the oxygen saturation concentration at 35.6º fahrenheit is 13.86 ppm. Next, raise the water temperature to 60º fahrenheit, and measure the dissolved oxygen again. It's dropped to 9.82 ppm. Finally, raise the same water to a temperature of 86º fahrenheit, and the oxygen concentration drops to 7.44 ppm. As the water gets warmer, the amount of dissolved oxygen goes down.

Light influences oxygen contentAll bodies of water, including properly illuminated indoor tilapia ponds, have phytoplankton. They are tiny green algae that live suspended near the water surface. When the water is illuminated, the phytoplankton begin their photosynthesis, which in turn, gives off oxygen. This oxygen is easily dissolved into the water, and by late afternoon, can significantly increase the amount of oxygen available to the tilapia. However, this condition is only temporary, and as soon as the sun goes down, or the lights are turned off, the phytoplankton stop producing oxygen. The result can be an oxygen drop to levels that are deadly for tilapia. This is why it is very

important to measure the dissolved oxygen content at least once at 4:00 a.m., then later that afternoon at around 2:00 p.m. The morning reading must be above 3 ppm (preferably 4 ppm). Then, the afternoon reading can be used as guide to determine when to take another early morning reading.

Decomposition depletes oxygenThe decomposition of organic matter uses oxygen, and gives off carbon dioxide. This creates the worst possible scenario for tilapia farming. Without immediate intervention, this can wipe out an entire harvest in one night. The night time drop in the oxygen created by photosynthesis, combined with the continued oxygen consumption of decomposing organic material, and subsequent release of carbon dioxide, which occurs around the clock, can cause the dissolved oxygen level to drop to almost nothing. This is why it is so important to remove tilapia poop and uneaten food from recirculating aquaculture systems, as quickly as possible, as part of the continual flow of filtration.

Maximize surface aeration before considering alternativesMore often than not, low dissolved oxygen levels are the result of inadequate surface aeration. It's easy to forget that the gas exchange only occurs at the surface, and only in the area affected by the aeration technique. For example, the spray from a fountain head only affects the area where the drops actually hit the water. So, if you have a pond with a surface area of 1800 square feet, and you only aerate a six foot circle, you still have 1774 more square feet to work with. Tilapia don't care if you make it rain 24/7 on the entire water surface, they'd much rather breathe. Finally, when you've exhausted every surface aeration option, and removed as much decomposing organic matter as you can, it might be time to consider thinning the number of tilapia in your pond.

Adding supplemental oxygenAdding supplemental oxygen requires an oxygen source and a method to dissolve the oxygen into the water. There are only three oxygen sources to choose from, and as you probably suspected, each has its own advantages, and disadvantages. Bottled oxygen gas is the simplest to deploy, and is the cheapest source of short-term oxygen. Make sure that it's medical grade

oxygen, not oxygen intended for welding. Liquid oxygen is cheaper in bulk than oxygen gas, but it is a fire hazard, and requires special training to handle, and may require special permits to be on your property. In addition, liquid oxygen requires special equipment to make it suitable for use. Generated oxygen has the highest up-front costs, but over time, can save money over the other two oxygen sources. Generally speaking, the end result from every oxygen source is a tube, with oxygen gas flowing, under regulated pressure. It's pretty easy to understand.The method used to dissolve oxygen into the water, on the other hand, is widely misunderstood. This, once again, stems from the fact that manufacturers are keenly aware that their customers don't understand the physics behind dissolving oxygen into water. The truth is, all that it takes to dissolve oxygen into water, is a hole in the ground, a couple pieces of pipe, and some fittings. But, what manufacturer is going to tell you that their system, costing thousands of dollars, can be usurped with parts from home center store? Not to mention the fact, that the custom-built unit, is 100 percent efficient, wastes no oxygen, has infinite range of adjustment, and can create dissolved O2 levels as high as 150 parts per million. Manufacturers would much rather capitalize on pseudo-science, selling snake oil remedies, and fancy packaging.Methods, such as flat-plate ceramic air diffusers, make very tiny bubbles. And, to the layman, make perfect sense. Supposedly, as the air bubbles slowly rise to the surface, the oxygen contained in each tiny bubble, comes in contact with the water, and some of that oxygen is "dissolved". Okay, but assuming that the bubbles are full of pure oxygen, why don't they completely disappear? The truth is, most of the oxygen simply rises to the surface, where each bubble breaks a tiny hole in the surface tension layer, and releases its oxygen into the atmosphere. Sure, a little bit of the oxygen gets into the water along the bubble's journey, and it's certainly handy to have all that oxygen concentrated right there on the surface, when the tension is broken, and the gas exchange occurs; but this method is not much more effective than surface aeration.The other predominant method of dissolving oxygen into water is with the use of an oxygen cone. An oxygen cone works by bubbling oxygen up through a rapidly decelerating column of water. The bubbles of oxygen are held in place by the opposing forces

(buoyancy vs. velocity), until they are absorbed. There are other variations on the oxygen cone theme, but this method is really the only other one that works, without wasting a lot of oxygen. The downside of oxygen cones, are their price and limited range of adjustment. For example, if the water flow is too strong, the bubbles get pushed out before they can dissolve; and if the water flow is too low, the bubbles will rise to the top, where they aren't effective.

U-Tube Oxygen GenerationThe best method for dissolving oxygen into water is with the use of a U-Tube. This method uses hydrostatic pressure to effortlessly move a column of water through a gradient of increasing pressures that crush the oxygen into the water. This is nothing new, in fact, it dates all the way back to 1647, when Blaise Pascal first formulated the concept of pressure, and how it is transmitted by fluids, such as water. The reason that you've never heard of this, is that there is no money to be made telling people how to do things for free; also, there's the fact that any search for u tube, ultimately gets you nowhere.The construction of a u-tube is fairly straightforward. All you do is drill a hole in the ground anywhere from 150 to 300 feet down. You will most likely hire a well driller for this job. Since you aren't going to be drawing water out of the hole, you probably won't even need any permits, but check with your local officials, just to be sure. After you have your hole, run a long "U" shaped section of pipe to carry water down the hole and back up again. Thanks to the equalizing pressure on each side of the u-tube, a low horsepower pump is all that is necessary to push the water along. Remember, it's all about low energy consumption. Just make sure that the flow is fast enough to carry the bubbles down.

Click on the picture for a larger version, it's pretty self-explanatory.

3. FoodThe fact that tilapia need food may seem just a little too obvious, for a guide that assumes its readers have an average level of common sense, but the amount of misinformation about feeding tilapia is appalling at best, and deadly at the worst. Contrary to Internet lore, tilapia do not seek out poop as a food source. Tilapia farming opeartions in China have been observed feeding pig manure to their fish, and the fish seem to eat it willingly. But what animal on earth won’t eat anything that appears to be edible, when it is offered no other choice. The truth is, just about all omnivorous fish will eat each others poop, as part of their inherent grazing and strike reactions. They aren’t swimming around the pond thinking “I could really go for some poop right now”. The poop from pigs and humans is just plain disgusting. Like pigs, humans seem willing to eat just about anything, including the poop of many sea creatures, including oysters, clams and shrimp. Don’t even get me started on the humans who drink the water squeezed from elephant crap, or eat dung beetles. It’s no wonder that we seem willing to believe that a tilapia would consider poop a savory edible, considering all the fecal material that we pay good money to eat in our lifetimes.Critical Point: Don't confuse the above statement about Chinese fish farms with the practice of "fertilizing" algae growth in ponds, as the Chinese would have you believe. Theres a big difference between suspending chicken coops over ponds to promote algae growth, and what the Chinese fish farmers are doing. Incidentally, fertilizing ponds with manure is still practiced today, in spite of a very exhaustive Taiwanese study, proving it useless.So what do Tilapia eat? Well, tilapia are omnivores, but they have very strong tendencies towards being vegetarian. The tooth and jaw structure of a tilapia is designed to graze on algae, and other aquatic plants. If you want to observe accelerated growth in tilapia fry, put them in an algae-covered aquarium, next to a sunlit window. They will devour the algae, growing much faster than the fry that are only given a commercial omnivorous fish food. Here at our hatchery, we feed our newly hatched fry organic algae discs, to get them up to size quickly. This also gets them out of the “danger

zone” faster, since tiny fry are far more delicate, and susceptible to pathogens, than larger fingerlings.Just about everyone knows that tilapia need food to grow, and it's not much of a stretch to understand that the more your tilapia eat, the faster they will grow. Although technically, just eating the food isn’t the secret to growth; it needs to be metabolized with the aid of oxygen, proper water chemistry, and temperature, as stated earlier in this guide. However, for the purposes of our explanation, we’ll just say that more food equals faster growth. One thing that catches new tilapia farmers by surprise, is the practice of using less food to slow growth. The main reason for slowing growth, especially in fingerlings, is to hit a target harvest date. Many farmers like to get their fingerlings early, and grow them indoors, over the winter, to reduce the cost of pond heating. If the tilapia get to a size where the indoor space is starting to get a little too cramped, the tilapia farmer can reduce the amount of food offered, to slow their growth. It should also be noted, that this practice should only be carefully administered, to avoid the risk of stunted growth.Nothing contributes to tilapia health more than good nutrition. The proper diet will boost their immune system, and help them resist disease. When combined with an ultraviolet sterilizer, to boost the Redox potential in your pond, proper nutrition will make your tilapia ready for just about anything. But, what constitutes proper nutrition? Well, when you consider that thousands of years of evolution have adapted their physiology to get everything that they need from algae and aquatic plants, then aquatic greens is the answer. Unfortunately, tilapia eat algae and plants much faster than they can grow back in a small area. In the wild, tilapia schools graze over several miles. A commercial tilapia farmer, intent on feeding only aquatic greens, would need to dedicate several square feet of water surface area, to grow sufficient food for a single tilapia. As with all commercial livestock farming, dedicating acres of valuable land to serve as the sole source of animal food just isn’t practical, and just about every farmer supplements, or completely replaces, the livestock’s natural diet with a nutrient-dense manufactured food.While not exactly what evolution has designed them to eat, tilapia do extremely well on some commercially produced food. The consistency of a manufactured diet offers many advantages to the tilapia farmer, that a natural diet would not. The even distribution of

nutrients, and uniformity of size, goes a long way to ensure that every tilapia in the pond gets the same level of nutrition. The amount of food to give, is determined by the weight of the fish and the temperature of the water. Uniformity between individual bags of food, keeps projected growth rates, and harvest dates, on track. Best of all, some manufactured tilapia food is scientifically designed for the fastest growth possible, when a proper feeding schedule is followed. So now the question is, how much food do tilapia need?To determine how much food to feed tilapia, you need to know three things: The water temperature, the average weight of each tilapia, and the the biomass; which is just a fancy word for the total weight of the living organisms per cubic foot of water, or for our purposes, just the total weight of all of the tilapia. As the water gets colder, tilapia metabolize food slower, and grow slower, so they need less food. The opposite is also true as the water gets warmer. During the early stages of growth, up to about 2 ounces, tilapia are eating machines, that can devour much higher percentages of their body weight per day, but as they grow, that percentage goes down, until they can only eat between 1.5 and 4 percent of their body weight per day. Obviously, since you don’t feed tilapia individually, it’s helpful to know the total weight of all of the tilapia in your pond, so that everyone gets to eat their fill.There are a lot of scientific calculations that you can do to determine the perfect amount of food to give each day, and if you're inclined to do all of the math yourself, we urge you to continue on your quest to become the ultimate tilapia nerd. For the rest of us, there are charts and graphs, made by other nerds. Here’s one for Purina AquaMax, the most nutritionally advanced tilapia food in the world.

The Purina chart is a bit generalized, but it’s still a decent guide for using their products, and it illustrates a couple of important facts about tilapia food consumption in general. Compare the Fish Weight in Grams column, to the Product Size column, and you’ll see that as the weight of each individual fish increases, the size of the food grains also increases. This part is obviously because bigger mouths can eat bigger food. Now, have a look at the column titled lb. of feed/100 lb of fish/day. That’s just another way of saying “percentage of body weight to feed”. All of the numbers in that column can also be read as a percent. For example, 20 percent or more, 11 to 20 percent, 4 to 11 percent, and so on. Notice that, as the tilapia get bigger, it takes fewer individuals to make a pound of fish, and the percentage of food to body weight goes down. This is because as tilapia get bigger, their rate of growth slows. Finally, notice the red area on the chart that shows the optimal feeding water temperature of 80-88 degrees Fahrenheit. As tilapia get colder, they metabolize less food, and therefore eat less. Another reason why selecting the right tilapia species for your operation, and giving some thought to your harvest dates, is so important.

Warning: Like everything else in the tilapia farming world, there are opportunists trying to turn a quick buck selling marginal nutrition as premium fish food. Most of this food is custom labeled, mass-produced, generic garbage composed of farming wastes. Anyone who wants to start their very own fish food company, can have their name and logo put on the bag. There's even an organic version that contains a plethora of indigestible ingredients, including peat, clay, diatomaceous earth, granite dust, and lots of metal oxides and sulfates. Whatever you save using their low cost food today, you will lose as a result of extended grow-out periods. It's definitely not a good choice. We urge you to check out our Tilapia Feeding Guide to learn more.There is an alternative method that is far more accurate than any food manufacturers feeding chart. Simply sort your fingerlings by size, which is akin to their rate of growth at this stage, and put them into separate ponds, making a note of how many tilapia you have in each sorted pond. Next, pull a net full of fish from one of your ponds into a previously weighed bucket of water, and weigh it again. The difference is the weight of the tilapia. Then count how many fish you weighed, as you put them back into their pond. Divide the total number of fish in the pond, by the number of fish you just weighed, then multiply the result times the weight you just measured, to get the total weight of the fish in the pond. Repeat this for each sorted pond. By the way, the above method is how we do it, but you can use any method you want to determine the total weight of the tilapia in your pond(s). Once you know the total weight of your tilapia, the rest is easy.Multiply the total weight of your tilapia in each pond by .015 and .018. These are the upper and lower amounts to feed the tilapia each day for optimal growth, at a water temperature of 84 degrees Fahrenheit. The reason for the upper and lower range has more to do with practicality than science. The idea is to give yourself a bigger target to hit when you are pouring food into a container on a scale, or adjusting an automatic feeder, so just go with it. Now obviously, after your fish have eaten, their weight will increase, so if you use the same calculation the next day, you will be feeding too little for optimal growth. So the question is, how much weight did they gain? Believe it or not, they gained the exact amount that you fed them, assuming that they ate it all, and the filtration system didn’t eat some for them. That means that if you fed your fish one

pound of food, they have gained one pound as a group. So take the previous days fish weight, add in the newly gained weight, and multiply the new total weight by .015 and .018 again, to get the new amount to feed. Keep a notepad handy, and do the calculation every day, and you will always be feeding the perfect amount for optimal growth.The golden rule of feeding is that if your tilapia can't eat all of their food in under 15 minutes, feed them less. A couple of factors can affect how much food your tilapia will eat, including colder temperature and disease. Look for signs that you are over feeding, such as uneaten food, or filters becoming abnormally “full” in a short period of time. If you lower the amount being fed, and there is still uneaten food, take a careful look at your tilapia for signs of disease; such as swimming slowly or lethargic, an apparent lack of fear of your hand, lack of buoyancy, sores, etc. Check their water temperature to make sure that it’s not near the bottom end of their survivability range. If everything checks out, then lower their food even more. Remember that tilapia can go for several days without food, so don’t be squeamish about lowering their food until it’s all being eaten. Oh, and please recheck your calculations. Many farmers have accidentally forgotten a zero, and multiplied the weight by .15 instead of .015.Finally, do not assume that if your water turns brown, it is due to overfeeding. A light brown tint is perfectly normal. That said, if you are over feeding, and you have poor water circulation, so that uneaten food isn’t getting trapped in the filter, it may be rotting at the bottom of the pond. This will make your water very dark brown and in the worst cases, foul smelling. Adding a small circulation pump, to create underwater currents that push wastes towards the filter outlet, and adding some carbon bags to your filtration system to reduce the smell, should fix these problems.

We sell three varieties of Purina AquaMax on our Tilapia Food For Sale page. And if you're looking for some professional day-to-day feeding charts, have a look at our Tilapia Feeding Guide.4. LightIf you’ve ever seen an aquarium of tilapia fingerlings at night, the sight is rather disturbing. Hundreds of fish swirling around, like dead bodies, seemingly trapped in the invisible underwater currents.

When you first turn on the lights, the only way that you’ll know that they aren’t all dead is that they are upright, instead of upside down and sideways. It’s very clear that tilapia need light to survive. Without light, they won’t move or eat, and they will die. So the question is, how much light is needed?In aquariums, tilapia can be observed hovering in the path of a beam of sunlight, as it shines through their water. In aquaculture ponds where there is a mix of direct sun and shade, tilapia seem to prefer the sunny side over the shaded side. There are several explanations for this behavior; many of them plausible. But whichever theory you are inclined to believe, it's obvious that tilapia prefer a bright, pond-filling, light.At our hatchery, we provide our tilapia with 18 hours of light per day, using a combination of sunlight and electric light, that stays on until midnight. Why? Because the longer that tilapia have light, the longer they will stay active; the more they will eat, and the faster they will grow. There are a lot of tricks to running a successful hatchery (or farm), and using light to extend the hours of food metabolism is one of them.Of course, the best light that you can give to your tilapia comes directly from the sun. In addition to being a very powerful source of light, sunlight can be directed with the use of solar tubes and mirrors, to create pond-filling illumination. In outdoor ponds, brightly illuminated shade is just about right. The kind of light found inside a plastic covered cold frame greenhouse, is another great example. If you can provide partial direct sunlight for your tilapia, that's even better. On top of everything, sunlight is completely free, automatically making it the best choice for commercial tilapia farming. In fact, the only downside to sunlight, is the unwanted wavelengths of light that come with it, such as Ultra Violet and Infrared.The second best lighting source for any pond, commercial or residential, is one that delivers photosynthetically active radiation or PAR. These are the lights used by hydroponic and aquaponic growers, because they deliver the full spectrum of light used by plants for photosyntheses. They do not emit the photons (light) that can be damaging to cells and tissues, like shorter wavelength lights can; and for the most part, the entire PAR spectrum is within the

visible range of the human eye. In other words, they're pretty safe for humans and fish. These are also the preferred lights to use for "extending the day" for fish activity. In addition, they work perfectly to grow plants, if that is part of your tilapia farming operation.PAR lighting comes in many different forms. Some of the most popular are High Intensity Discharge (HID) types, such as High Pressure Sodium (HPS) and Metal Halide (MH) For commercial tilapia farming, HID lights are preferable, due to their intensity, which allows the light source to be placed farther from the water. Other options, such as PAR spectrum fluorescent lights are inexpensive. However, their relatively low output, requires that they be placed closer to the water surface than HID lighting. Newer technologies, such as LED and Plasma, use much less energy, and produce very little heat. Unfortunately, they also come with a very high price tag.As a last resort, you can use single wavelength fluorescent lighting, provided that they are daylight balanced to between 5000 and 5500 degrees Kelvin. In case you didn't already know, Kelvin is a color temperature, not a measure of heat, or wavelength, as previously mentioned. It's comparable to the hue of a light source, if that helps you understand it better. Sunlight has a color temperature of between 5000 and 5400 degrees Kelvin, and overcast skies are 5500 to 6000 degrees Kelvin. You can get daylight balanced fluorescent bulbs at any home center store; you do not need to buy expensive aquarium lighting. Just as important as the color temperature, is the actual wattage. Your bulbs need to have enough power to cut through the water and light the bottom of your pond. Even still, fluorescent lighting pales in comparison to direct or indirect sunlight and HID lighting.

5. Room To SwimTilapia tolerate crowded conditions better than most species of fish, but they do have their limits. Increased numbers of tilapia can easily deplete the shared oxygen supply faster than it is being replaced. Oxygen that hovers at barely survivable minimums can cause damage to organs and other sensitive tissues, leading to illness. Overcrowding causes stress that leads to slower immune system response and poor resistance to disease. In addition, lowered oxygen levels also reduce the Redox potential of water, making tilapia even more susceptible to pathogens. The triple whammy of

stress, reduced oxygen, and lowered Redox, are an open invitation for diseases like Streptococcus, Aeromonas, or Columnaris, none of which can be cured economicallyIn a clean water pond, normal surface aeration will support a density of two pounds of tilapia for every cubic foot of water. That's a one pound tilapia for every 3.74 gallons of water. With the use of supplemental oxygen, a density of five pounds per cubic foot can be achieved. The highest documented tilapia farming density that we have found, was seven pounds per cubic foot. However, this was an experimental system, that utilized liquid oxygen to raise the O2 levels above 150 ppm.Reality Point: It is being falsely stated, by several tilapia fingerling sellers, and aquaponic systems dealers, that a "density" of one fish per gallon of water is "what everybody does". This is a marketing fabrication, and is only possible if they intend for their customers to harvest their tilapia when they reach ¼ of a pound, yielding a couple of one ounce nuggets.It's important to distinguish between the volume of water in a system, and the area of water available to the tilapia. While the volume of water plays a role in the available dissolved oxygen, it does not have an affect on the stresses caused by the close quarters of an overcrowded environment. Even in open water tilapia farming, where the tilapia are raised in suspended nets, with potentially endless dissolved oxygen, over crowding can lead to disease, food suppression, and slowed growth. To combat food suppression in crowded ponds, Purina makes an AquaMax food specifically for dense tilapia farming. The smaller pellet size means more pellets per pound of food, and gives every tilapia a chance to grab a mouthful at every feeding.Critical Point: Some small tilapia farmers use volumizing tanks, or have a large amount of water contained in aquaponic floating rafts, but this water should not be considered when calculating the density of a tilapia pond. Only the area that is occupied by tilapia counts.So that's it for the five needs of tilapia, let's move on to part 2 - tilapia farming systems.9068

About this guideThis guide is intended to teach people interested in home tilapia farming, how to set up, and cultivate, a tilapia pond. But tilapia need much more than just a pond. Tilapia need five things to grow fast and healthy: clean water, oxygen, food, light, and room to swim. We have already written an extensive tilapia farming guide that covers these five needs on our main website at lakewaytilapia.com so we will avoid repeating them here. There are other articles on our main website that will help you select the right tilapia species for your needs, and review your states legal information about tilapia farming. We urge you to use all the resources that we have provided, and by all means, call us if you have any questions.Aquaponics or traditional gardeningThe purpose of this site, Backyard Tilapia, is to educate people interested in home tilapia farming about raising and harvesting tilapia, not how to grow vegetables. That said, one of the responsibilities of any home tilapia farmer is the disposal of tilapia wastes, and nitrate heavy water. Both aquaponics and traditional gardening offer excellent solutions to this problem, and each of these methods have their own merits.Aquaponics works by recirculating the nitrate heavy water, after the solid wastes have been separated out, through hydroponic grow beds filled with a growing media, or floating rafts.  The plants in the grow beds use the nitrates as fertilizer, slowing the build up of toxins, and delaying the frequency of water changes. The main downside of aquaponics for many people, is the initial cost to set up a system large enough to support the number of tilapia that they want to raise. Arguably one of the biggest benefits of aquaponics, from the tilapia farming perspective, is that there is less waste water to dispose of. The bottom line is... If the space is tight, and water conservation is a concern, aquaponics is a great way to turn dirty tilapia pond water into delicious fruits and vegetables.Traditional earth gardens benefit from tilapia waste water when it is used it to directly irrigate crops. Fresh water is continually added to

the tilapia grow out ponds at a rate of about 3 percent of the total volume per day. The overflow passes to a holding tank, where it is stored for watering the garden. A small well pump inside the holding tank, connected to a pressure tank, will supply everything form a garden hose to an advanced irrigation system. Of course on smaller ponds you can do traditional aquarium style water changes using a siphon hose to remove 20 percent of your pond water to you garden each week, and replacing it with fresh water. The main downside of direct irrigation has to do with the volume of water that must be disposed of. Your garden will have to be big enough to handle 100 gallons of water for every 500 gallons of pond volume each week. And of course, the biggest benefit of direct irrigation is the very low set up cost.  The bottom line is... If you have the space for a large garden, and water is plentiful in your area, direct irrigation is probably the best water disposal method for you.

How To Build A Tilapia PondDetermine your tilapia pond size

A tilapia pond is nothing more than an above ground container filled with water. Examples for backyard tilapia farming use are kiddie pools, IBC Totes, fiberglass hot tubs, and lined plywood troughs. Of course, for commercial aquaculture or aquaponics, there are more industrial pond options, but that's beyond the scope of home tilapia farming, and this site. Tilapia need half of a cubic foot of water, or 3.74 gallons, for every pound of their body weight. So if you want to keep 144 pounds of fish in the same pond, you will need to have one that holds 72 cubic feet of water, or 538.56 gallons.  A lined plywood trough that is 4 feet wide, and 8 feet long, with 2.25 feet of water depth, and a 3 inch high edge, is the exact size needed; and is what we will be using in our build examples for the rest of this section. Of course, you can expand this pond to any size that you want.To figure out how many cubic feet, or gallons, you will need, simply decide how many pounds of fish that you want to harvest every six to nine months (depending on species), and then divide that weight in half to get the cubic feet. Then, multiply the cubic feet by 7.48 to get gallons. For example, if you want to have 144 pounds of tilapia in your pond at harvest time, take 144 and divide by two to get 72 cubic feet (144 / 2 = 72). Then, to get gallons, you just have to take

the cubic feet, and multiply by 7.48 to get 538.56 gallons (72 x 7.48 = 538.56).Once you know how many cubic feet or gallons you need, it's simply a matter of finding the right container to hold that much water; with a little lip at the top, so your tilaipa don't swim over the edge. To get the cubic feet of a rectangular pond, you multiply the length, times the width, times the water depth. To get the cubic feet of a circular pond, multiply the radius, times the radius (r squared), times 3.14 (pi), then multiply the result times the water depth.Determine your pond construction

The simplest solution to making a tilapia pond, is to use a kiddie pool. A twelve foot diameter kiddie pool filled with 24 inches of water holds 1696.46 gallons and costs very little. However, there are a couple of drawbacks to using one of these small pools as a pond. First, as the vinyl ages it tends to get very brittle, and will eventually split down the side. You can support the sides after the pool is filled by surrounding it with thin plywood, or similar flexible material, but this will only buy you a second season of use. The the best thing to do is replace the pool (or liner) every 24 months, or sooner. The second potential drawback to using a kiddie pool as a tilapia pond has to do with whether or not the fish are affected by the vinyl leaching chemicals into their water.Some fish are extremely sensitive to the chemicals leeched into their water by vinyl, but Tilapia are not on that list. So as far as your fish are concerned, a vinyl kiddie pool is as good as any other. But what about the fact that your tilapia are intended for human consumption? If you were farming tilapia at home to make extra money, by selling the filets, there is no way that a kiddie pool will pass the food safety guidelines established by the FDA; which you would be required by law to follow, if you wanted to sell your processed tilapia to consumers. But this has nothing to do with toxins from vinyl, it has to do with normal industrial practices, and the fact that the FDA only approves materials; they don't actually disapprove anything.Whenever we see a big government agency, like the FDA, make a list of approved ingredients or materials, we seem to consider it our patriotic duty to automatically assume that everything else is

disapproved, but this just isn't the case. The reason that the FDA has never approved the raising of tilapia in 45 gallon trash cans, is because it is not normal to do that. Since nobody wants to raise tilapia in a trash can, there's no reason for trash can manufacturers to seek FDA approval. The same goes for kiddie pool manufacturers. They aren't approved by the FDA, because they aren't intended for use as ponds. That doesn't mean that you can't use them as ponds, it just means that no government scientist has done a study on the effects of vinyl kiddie pools on fish intended for human consumption.Don't forget the fact that you will probably be doing regular water changes, and that any vinyl toxins will never get the chance to build up in the first place. So as far as using a kiddie pool goes, the choice is yours. Incidentally, during the writing of the above two paragraphs, a bit of research was done in an attempt to find a single scientific article on the affects of food fish spending six to nine months exposed to the low levels of chemicals found in vinyl liners, and none were found. Like everything else, there's a lot of fear mongering and rhetorical questions, but no scientific evidence. More than a few of our customers use kiddie pools, and their fish are healthy and delicious. Now, after all of that support for kiddie pools, we aren't even going to use one.  Instead, we are going to build a lined plywood trough.A lined plywood trough has many advantages over other forms of ponds for home tilapia farming. It's nearly indestructible. It can be any size. It makes harvesting tilapia easy. It's relatively inexpensive to build. And, just in case you want to expand into a small commercial tilapia farm, it can easily be made with FDA approved materials. So in the next section, we will take you through the steps required to build a simple lined plywood tilapia pond.Builder's Note: The pond in this example is designed to meet the minimum requirements for the home tilapia farmer. It is intended to be the lowest cost option, not the industry standard.Gather Your Materials and Tools.

For our pond project we will need the following:

12 - 10' 2x6 boards2 - 4x8 sheets of ½" plywood1 - Sheet of styrofoam insulation board 

Important:Do not use pressure treated wood, it is poisonous to fish.

1 - 10' x 13' fish safe pond liner (available at Lowes for $69) or equivalent sized Dura Skrim R20WW pond liner, if you plan on processing your tilapia for sale. Dura Skrim R20WW is organically certifiable and rated as food safe.Builder's Note: A white liner will make your tilapia easier to see in their pond. Also, we sell the Dura Skrim R20WW pond liner to our tilapia farming customers at a price that's below retail.Call 865-262-8289 for more details and pricing information.

A drill with a bit large enough to make holes for the carriage bolts you want to use.

1 - One pound box of 1¼ " deck screws. (I accidentally grabbed some drywall screws for the picture to the right, but they weren't used.)

Some Gorilla Glue.

A staple gun.

Some 10mm staples.

32 - 3½" carriage bolts with nuts and washers. (I used 3½ x 5/16)

Not shown are:A wrench to tighten the bolts.A hammer to help line things up and tap in carriage bolts.A few clamps.A roll of duct tape.

Construct your tilapia pond.

Cut the two sheets of plywood into three 30"x48" pieces each.

Cut four of the 2x6 boards into two 60" long pieces each.

Cut eight of the 2x6 boards down to 108" long each and cut the 12" scraps from each board down to 8" long each.

Also shown in this picture are:4 - 8" long 2x4 pieces which will be used. (The six 12" 2x4s shown will not be used)

Construct two walls as pictured to the right and below using the following for each wall:2 - 30"x48" pieces of plywood.4 - 108" long 2x6 boards.4 - 8" long 2x6 boards.2 - 8" long 2x4s

Attach the plywood to the 2x6 frame with Gorilla Glue and deck screws. Cover the deck screw heads and plywood seam with duct tape to protect the liner from chafing and developing holes.

Make sure that the plywood is centered over the framing and that there is 6 inches of 2x6 protruding past the ends as shown.

The eight inch verticals will prevent the plywood from bowing out at the corners over time. The 2x4s can be used at the top because there is less weight pushing outward.

At this point you can decide if you want to use water sealer on the side walls. Winter temperatures can create condensation which may cause some problems on unsealed wood.  We use dehumidifiers to control condensation on indoor surfaces in the winter and open ventilation in the summer.

You may also choose to build a 5 foot by 9 foot platform out of 2x4's and some plywood to raise your pond off of your floor. Some concrete floors can get very cold and act as a heat sink in the winter even with insulation. The particular floor under this pond does not get very cold in the winter, so we will be placing the pond directly on the floor.

Select a location for your pond away from building walls so that you can pick up tilapia that jump out during pond maintenance and to facilitate easy servicing of the filtration. You should also paint any drywall surfaces with gloss latex paint designed for wet locations, such as bathrooms.

Lay the sheet of styrofoam insulation board on the floor where you want your pond and use it to square up your pond sides.

After you have your sides perpendicular to each other using the styrofoam sheet, you can clamp the sides together using the 60" long 2x6s and pull the styrofoam sheet out of the way. Draw a diagonal line as shown in the photo below to help keep your carriage bolts towards the middle of each 2x6 board. Be sure to make the corners of the 2x6 boards flush as shown to maintain the ½ inch space for the plywood and to keep the interior dimensions exactly 4'x8' after the plywood is installed. By the way, if the numbers seem off, they aren't. A 2x6 board is actually 1½ x 5½ so the interior dimensions will work out in the end.

After you drill holes for the carriage bolts and use them to attach all the 60" long 2x6s this is what you should have. Note that the top board is attached underneath while the rest are on top. Also notice the ½" gap between the vertical pieces and the 60" horizontal ends.

Attach a 48"x30" piece of ½" plywood to each of the ends using the deck screws and Gorilla Glue. Cover the screw heads with duct tape. Also cover any sharp imperfections in the wood such a knots and cover the top edges of the plywood with duct tape.

Lay the sheet of styrofoam insulation at the bottom of your pond. If you've cut everything to exact dimensions, it should fit perfectly.

Loose fit the pond liner and hold it in place using staples. Be sure to only put staples along the top edge. The staples are only temporary and will be removed during filling.

Now for the least fun part of it all - removing wrinkles.

Wrinkles in the pond liner will trap wastes on their way to the filter pump, chafe against nets, and cleaning brushes, eventually turning into leaks. They must be removed, and there's really only one way to do it. You're going to have to get wet.

First, put one inch of water in the bottom of your pond. This water will hold the liner down as you push out the wrinkles. Do not put more than one inch of water, or the wrinkles will crush down, and you won't be able to push them out.

Starting in the center, and working your way outwards in a circular pattern, push the wrinkles towards the sides, using your thumbs. You might be tempted to use your fingers to pick up and pull on the liner, but don't do it because you will create more wrinkles

someplace else. Surrender to the fact that this is going to take a while, turn on the radio, and don't give up until every last wrinkle has been relocated to the sides of the pond.

After you have all the wrinkles moved to the sides, leave them alone, and put six inches of water in your pond. This amount of water weighs nearly one thousand pounds. Your pond liner isn't going anywhere.

Working on one side at a time, beginning with the long sides first, remove the temporary staples, and pull up on the liner to remove the wrinkles that were pushed to the sides. Be sure not to pull up on the liner so hard that you pull it away from the corners, and form a curved edge with an air pocket underneath. If you do, you'll have to get back into the water and work the side of the liner back into the corner. Once you have made the sides and the folds in the liner as smooth as you can, permanently staple the liner to the outside edges of the 2x6's, on the sides only. On the ends you will only use as many staples as necessary to hold the fold. Later on, the staples on one or both of the ends will be removed to add support for filtration, so only staple the ends in a semi-permanent fashion.

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Raising Tilapia - Growing Tilapia Fish Ponds for Food

Tilapia are a hardy, fast growing fish with a good (less fishy) taste ideal for warm areas or indoor heated tanks. They are somewhat boney and can be slightly difficult to clean.The most important thing to know about Tilapia is that there are many types, with wildly different characteristics. For example, the Mosambique breed like salt more than other tilapia.

And even within one type of Tilapia, the nutritional value of the fish will vary wildly depending on what they were fed. For example, if they are fed primarily corn they will contain more Omega 6 (harmful) than Omega 3 (helpful) fatty acids^. Fish grown on flax based feeds will be high in Omega 3s and low in Omega 6's.^ ^ Even for one individual Tilapia, the ideal temperature and diet will vary over the fish's lifetime.Very complete information on care, feeding, treatment, and diagnosis is available: Tilapia Health Diagnosis and Treatment AdviceEnvironmentTemperature: Every breed of Tilapia is different, but most Tilapia prefer temperatures of 77 to 86'F (25-30'C) and will not thrive or grow at lower temperatures. Some may tolerate temperatures as low as 47'F (8 or 9'C) for short periods (overnight). In an area where the temperature, at least through the growing season, is high enough to maintain water temperature in the preferred range, they may be grown outside in a pond. During very hot weather, ventilate or plant shade type water plants. Over-winter a few smaller fish in an indoor aquarium to serve as breeders next

spring if the winter temperature will be too low. In areas where pond water is too cold, Tilapia will need to be grown in tanks, barrels, or above ground pools which are insulated from the earth and heated or enclosed in a green house or tent. See: Tilapia Aquaculture Environment: TemperatureSpace: The size of the pond should be determined by the number of fish you want to raise. A good guide is 4 to 5 square feet of water per mature fish or 2-3 mature fish per square meter of water surface in a pond environment. In aquaculture or aquaponics, a more crowded environment can help keep the aggressive males from becoming territorial: No fewer than 3 fish per 50 gallons, and up to 12 adult fish can be contained in a 55 gallon drum. The water depth in any environment should be more than 3 feet or one meter; never less than 2.5 feet (three-fourths meter) deep. The water should be still and not flowing so if a stream or river is used, the pond should be separated from the flowing water. Exposure to sunlight is very important both to maintain temperature and to promote the growth of green food such as algae. See: Site Selection and EngineeringSalinity: They grow well up to salinities of 16 to 20 parts per thousand (sea water is 35 ppt). Salt can be added to discourage pests and to create a warmer layer in a deep pond during the winter. It can also help to control overpopulation: Fry numbers decline substantially at 10 ppt salinity. See: Tilapia Aquaculture Environment: SalinityWater Quality: No water filtration is typically required in a pond; water hyacinth can remove enough pollutants. In an aquaponics system, a bio-filter and regular water changes of about

20% per week or 10% twice a week are enough to maintain water quality in an established system. Unlike many other fish, Tilapia can eat algae so green water is not a bad sign; some manure and sunlight can provide additional "free" food without damaging the fish.

Chlorine must be removed from the new water by adding either commercial de-chlorination chemicals or 1000mg Vitamin C per 100 gallons water. If the water is treated with Chloramine^ then a special commercial chemical made to remove chloramine must be used or the water must be left to stand at least 24 hours after de-chlorination to allow the ammonia still present to dissipate. A bubbler in the water will accelerate the process. Tilapia are tolerant of more ammonia in their water than most pond fish, but they have limits. Chlorine and Ammonia test kits are expensive, but recommended especially when starting or when conditions or behavior changes. Ammonia test kits can be found at pet stores that sell fish. Chlorine test kits are available for less at pool supply stores. The cost can be reduced by testing only half the water and half the test chemicals.See: Tilapia Aquaculture Environment, Water QualityStockBreeders: If fingerlings are unavailable, you need about 20-30 pairs of good breeders to start reproducing in breeding pond of 10 x 20 feet. Stock 1:3 or 1:4 male to female. The bottom of the breeding pond must consist of lime or compost, about 16% Tilapia spawn

every 7 to 8 weeks. Eggs hatch in 2 to 5 days and the female guards the young for an additional 8 to 10 days.

Fingerlings: If fingerlings are available, you will need to plan on about 5 to 6 fingerlings per square meter of water surface area. The most common breeds of tilapia available are: Nilotica, Mozambique, and GIF (genetically modified). Fingerlings need large amounts of protein and will become canabilistic if unsatisfied. Feedings of grub, bugs, flies, worms are helpful.

In San Diego CA: http://www.mybackyardfishfarm.com Sells fingerlings for a very reasonable price. Also sells basic aquaponics systems for $149 and up. Basically a food grade 55 gallon drum, air pump, biofilter (with starter), and some fingerlings.   

In Smithville, MO: http://www.tilapiasource.comPreparationBefore stocking the pond with tilapia, be sure to drain it thoroughly and remove the weeds and unwanted fish that may be present. Allow your pond to dry up until it cracks before refilling with fresh, clean water.

Fertilize the pond one week before stocking. Apply chicken manure on the pond bottom with water depth of about 6 centimeters at the rate of one kilo for every lo square meters. Fertilize the pond once a month to insure good production of algae.

Stock the pond either early in the morning or late in the afternoon when the water temperature is low in order to avoid weakening of

the fish. Allow the water in the pond to mix gradually with the water in the fish container before putting the fish into the pond. For more, see: Pond Preparation and Management.Care and FeedingMaintain the natural blue green algae and Plankton by adding more fertilizer. Place 5 lbs (2.5 kg) of chicken droppings in each of several sacks and suspend in the water at every corner of the pond. The sack slows the release, preventing excessive oxygen depletion during decomposition. Supplement feeds with greens, duckweed, flax, wheat germ, fine rice bran, bread crumbs, eggs, earthworms, grubs, termites, and others at an initial rate of 5% of the total body weight of the fish. Avoid feeding more than the fish will eat in one session.

Plant shade type water plants during hot weather, but do not totally cover the pond with plants as this will interfere with the natural food production process. Other good plants include duckweed.

Overpopulation will slow the growth of the older fish; there are many non-chemical methods of reducing "recruitment" (the production of offspring) and some may even provide additional benefits. Fry numbers decline substantially at 10 ppt salinity. One method, which mimics nature, is the use of very low quantities of predatory fish to "pick off" excess fingerlings and sick adults. Possible predators include:

snakehead (Channa striata) Lates niloticus

While the production and consumption of the fingerlings by the predators does reduce the yield of the crop fish, the predators may also be used as food fish or to feed other producing stock such as Chickens.Disease and Treatment: See: HAMES: Practical diagnosis and adviceHarvest, Fillet, and CookingHarvesting is best done when the winter is near or some other factor means that the fish are unlikely to survive or unlikely to grow more. Fish can also be harvested whenever they are large enough to be of use, or on an as needed basis. There are several methods of quickly killing the fish, but chilling in an ice bath is the least violent and takes very little time. Tilapia have very strong scales and skin, so a very, very sharp knife is needed. A protective metal or thick leather glove is a good idea. Since they are covered in a protective "slime" they should be held down with a towel. Using a knife or kitchen scissors, cut from the anus toward the head to release the internal organs and scoop them out into a waste container. Clean the knife and the fish in running water, then start a cut at the tail, up along the top of the fish on one side of the spine, and then back down just behind the gill and under the front fin. Pry the side off while cutting along the ribs with downward strokes to sure as much of the meat is removed as possible. The carcass is ideal for soup stock with vegetables, bay leave, and perhaps rice. The fillet can then be turned over, and the skin separated by holding it with pliers and again making downward strokes with the knife against the inside of the skin to ensure as much meat is retained as possible.

Of course, there are many ways to cook tilapia, but a light coating in flour, with some salt and pepper, sauted in olive oil for just one minute on each side is easy, quick, and delicious. Do not overcook! Served with a slice of lemon and tartar sauce or capers.

IdeasMost tropical fish, including Tilapia, grow best above 80'F. If they need heat, and the water filter needs a UV stage, why not add an open air solar water heater to do both? A shallow tray with black backing over which the water is pumped may raise the temperature even without a cover. In colder areas, a thin cover of UV transparent plastic may be required. Most PMMA, Acrylic, and other UV "resistant" materials will pass UV; they are resistant because they do not absorb UV energy. A wind pump can be used to move water through the panel, but a solar PV powered electric pump makes more sense as it will automatically run when the sun is out.Tilapia can live in fresh or salt water... That might allow us to raise the temp by making the pond a solar salt pond. In an ordinary pond, the sun’s rays heat the water and the heated water from within the pond rises and reaches the top but loses the heat into the atmosphere. The net result is that the pond water remains at the atmospheric temperature. The solar pond restricts this tendency by dissolving salt in the bottom layer of the pond making it too heavy to rise.

Another suggestion (thanks bbob) is just covering the pond with a clear material (like plastic or glass) to retain heat. In a high activity (read: kids) area, glass might be broken, but bbobs idea of just

floating bubble wrap on it is pure brilliance! And it will keep a little air on the surface of the water under the plastic.

 

Studies 1 with some species of tilapia show that "monoculture" (male only) ponds do not produce significantly higher yields than "mixed" (male and female) ponds.

From The Perfect

Fish http://www.aquanet.com/features/tilapia/perfectfish.htm Since "everyone knows" that female tilapia grow slower than male tilapia, scientists came up with a method of treating all of the tilapia fingerlings with male hormones so those fish that would have been female now turn out to be male. Then all of the fish in the growing tanks or ponds will be male, and the average growth rate will be higher than it would have been with half males and half females. Now even the US government supports the use of reversal techniques by allowing   all of the tilapia hatcheries who wish it to participate in what is known as an INAD. This basically means they have the right to put chemicals into the food of the fish that are not yet cleared as being safe, as long as they send results in to the government.

Almost every tilapia grower now uses hormone-treated fingerling tilapia. This basically reduces the time it takes to get the tilapia

through the growing stage and hopefully allows for slightly higher profits from the sale of the fish since a farmer can grow more each year.

The truth is, however, that the only tilapia that grow faster if they are treated with methyl testosterone are the of the "pure line" species. These are produced by breeding, say, males of tilapia nilotica to female tilapia nilotica. If hybrids are produced using t. nilotica and T. aurea or T. mozambique and T. hornorum, any females that are produced will tend to grow as fast as the original male tilapia in the pure line species.

Ocean Rich, Tilapia hatchery and farm in Thermal, California, ph (760)397-7302, fax (760)397-6101Scientific American article by C.F. Hickling, "The Cultivation of Tilapia,"

Also:

See also:

Raising Tilapia - Growing Tilapia Fish Ponds for FoodTilapia are a hardy, fast growing fish with a good (less fishy) taste ideal for warm areas or indoor heated tanks. They are somewhat boney and can be slightly difficult to clean.

The most important thing to know about Tilapia is that there are many types, with wildly different characteristics. For example, the Mosambique breed like salt more than other tilapia.

And even within one type of Tilapia, the nutritional value of the fish will vary wildly depending on what they were fed. For example, if they are fed primarily corn they will contain more Omega 6 (harmful) than Omega 3 (helpful) fatty acids^. Fish grown on flax based feeds will be high in Omega 3s and low in Omega 6's.^ ^ Even for one individual Tilapia, the ideal temperature and diet will vary over the fish's lifetime.Very complete information on care, feeding, treatment, and diagnosis is available: Tilapia Health Diagnosis and Treatment AdviceEnvironmentTemperature: Every breed of Tilapia is different, but most Tilapia prefer temperatures of 77 to 86'F (25-30'C) and will not thrive or grow at lower temperatures. Some may tolerate temperatures as low as 47'F (8 or 9'C) for short periods (overnight). In an area where the temperature, at least through the growing season, is high enough to maintain water temperature in the preferred range, they may be grown outside in a pond. During very hot weather, ventilate or plant shade type water plants. Over-winter a few smaller fish in an indoor aquarium to serve as breeders next spring if the winter temperature will be too low. In areas where pond water is too cold, Tilapia will need to be grown in tanks, barrels, or above ground pools which are insulated from the earth and heated

or enclosed in a green house or tent. See: Tilapia Aquaculture Environment: TemperatureSpace: The size of the pond should be determined by the number of fish you want to raise. A good guide is 4 to 5 square feet of water per mature fish or 2-3 mature fish per square meter of water surface in a pond environment. In aquaculture or aquaponics, a more crowded environment can help keep the aggressive males from becoming territorial: No fewer than 3 fish per 50 gallons, and up to 12 adult fish can be contained in a 55 gallon drum. The water depth in any environment should be more than 3 feet or one meter; never less than 2.5 feet (three-fourths meter) deep. The water should be still and not flowing so if a stream or river is used, the pond should be separated from the flowing water. Exposure to sunlight is very important both to maintain temperature and to promote the growth of green food such as algae. See: Site Selection and EngineeringSalinity: They grow well up to salinities of 16 to 20 parts per thousand (sea water is 35 ppt). Salt can be added to discourage pests and to create a warmer layer in a deep pond during the winter. It can also help to control overpopulation: Fry numbers decline substantially at 10 ppt salinity. See: Tilapia Aquaculture Environment: SalinityWater Quality: No water filtration is typically required in a pond; water hyacinth can remove enough pollutants. In an aquaponics system, a bio-filter and regular water changes of about 20% per week or 10% twice a week are enough to maintain water quality in an established system. Unlike many other fish, Tilapia can eat algae so green water is not a bad sign; some manure and

sunlight can provide additional "free" food without damaging the fish.

Chlorine must be removed from the new water by adding either commercial de-chlorination chemicals or 1000mg Vitamin C per 100 gallons water. If the water is treated with Chloramine^ then a special commercial chemical made to remove chloramine must be used or the water must be left to stand at least 24 hours after de-chlorination to allow the ammonia still present to dissipate. A bubbler in the water will accelerate the process. Tilapia are tolerant of more ammonia in their water than most pond fish, but they have limits. Chlorine and Ammonia test kits are expensive, but recommended especially when starting or when conditions or behavior changes. Ammonia test kits can be found at pet stores that sell fish. Chlorine test kits are available for less at pool supply stores. The cost can be reduced by testing only half the water and half the test chemicals.See: Tilapia Aquaculture Environment, Water QualityStockBreeders: If fingerlings are unavailable, you need about 20-30 pairs of good breeders to start reproducing in breeding pond of 10 x 20 feet. Stock 1:3 or 1:4 male to female. The bottom of the breeding pond must consist of lime or compost, about 16% Tilapia spawn every 7 to 8 weeks. Eggs hatch in 2 to 5 days and the female guards the young for an additional 8 to 10 days.

Fingerlings: If fingerlings are available, you will need to plan on about 5 to 6 fingerlings per square meter of water surface area.

The most common breeds of tilapia available are: Nilotica, Mozambique, and GIF (genetically modified). Fingerlings need large amounts of protein and will become canabilistic if unsatisfied. Feedings of grub, bugs, flies, worms are helpful.

In San Diego CA: http://www.mybackyardfishfarm.com Sells fingerlings for a very reasonable price. Also sells basic aquaponics systems for $149 and up. Basically a food grade 55 gallon drum, air pump, biofilter (with starter), and some fingerlings.   

In Smithville, MO: http://www.tilapiasource.comPreparationBefore stocking the pond with tilapia, be sure to drain it thoroughly and remove the weeds and unwanted fish that may be present. Allow your pond to dry up until it cracks before refilling with fresh, clean water.

Fertilize the pond one week before stocking. Apply chicken manure on the pond bottom with water depth of about 6 centimeters at the rate of one kilo for every lo square meters. Fertilize the pond once a month to insure good production of algae.

Stock the pond either early in the morning or late in the afternoon when the water temperature is low in order to avoid weakening of the fish. Allow the water in the pond to mix gradually with the water in the fish container before putting the fish into the pond. For more, see: Pond Preparation and Management.Care and Feeding

Maintain the natural blue green algae and Plankton by adding more fertilizer. Place 5 lbs (2.5 kg) of chicken droppings in each of several sacks and suspend in the water at every corner of the pond. The sack slows the release, preventing excessive oxygen depletion during decomposition. Supplement feeds with greens, duckweed, flax, wheat germ, fine rice bran, bread crumbs, eggs, earthworms, grubs, termites, and others at an initial rate of 5% of the total body weight of the fish. Avoid feeding more than the fish will eat in one session.

Plant shade type water plants during hot weather, but do not totally cover the pond with plants as this will interfere with the natural food production process. Other good plants include duckweed.

Overpopulation will slow the growth of the older fish; there are many non-chemical methods of reducing "recruitment" (the production of offspring) and some may even provide additional benefits. Fry numbers decline substantially at 10 ppt salinity. One method, which mimics nature, is the use of very low quantities of predatory fish to "pick off" excess fingerlings and sick adults. Possible predators include:

snakehead (Channa striata) Lates niloticusWhile the production and consumption of the fingerlings by the predators does reduce the yield of the crop fish, the predators may also be used as food fish or to feed other producing stock such as Chickens.

Disease and Treatment: See: HAMES: Practical diagnosis and adviceHarvest, Fillet, and CookingHarvesting is best done when the winter is near or some other factor means that the fish are unlikely to survive or unlikely to grow more. Fish can also be harvested whenever they are large enough to be of use, or on an as needed basis. There are several methods of quickly killing the fish, but chilling in an ice bath is the least violent and takes very little time. Tilapia have very strong scales and skin, so a very, very sharp knife is needed. A protective metal or thick leather glove is a good idea. Since they are covered in a protective "slime" they should be held down with a towel. Using a knife or kitchen scissors, cut from the anus toward the head to release the internal organs and scoop them out into a waste container. Clean the knife and the fish in running water, then start a cut at the tail, up along the top of the fish on one side of the spine, and then back down just behind the gill and under the front fin. Pry the side off while cutting along the ribs with downward strokes to sure as much of the meat is removed as possible. The carcass is ideal for soup stock with vegetables, bay leave, and perhaps rice. The fillet can then be turned over, and the skin separated by holding it with pliers and again making downward strokes with the knife against the inside of the skin to ensure as much meat is retained as possible.

Of course, there are many ways to cook tilapia, but a light coating in flour, with some salt and pepper, sauted in olive oil for just one

minute on each side is easy, quick, and delicious. Do not overcook! Served with a slice of lemon and tartar sauce or capers.

IdeasMost tropical fish, including Tilapia, grow best above 80'F. If they need heat, and the water filter needs a UV stage, why not add an open air solar water heater to do both? A shallow tray with black backing over which the water is pumped may raise the temperature even without a cover. In colder areas, a thin cover of UV transparent plastic may be required. Most PMMA, Acrylic, and other UV "resistant" materials will pass UV; they are resistant because they do not absorb UV energy. A wind pump can be used to move water through the panel, but a solar PV powered electric pump makes more sense as it will automatically run when the sun is out.Tilapia can live in fresh or salt water... That might allow us to raise the temp by making the pond a solar salt pond. In an ordinary pond, the sun’s rays heat the water and the heated water from within the pond rises and reaches the top but loses the heat into the atmosphere. The net result is that the pond water remains at the atmospheric temperature. The solar pond restricts this tendency by dissolving salt in the bottom layer of the pond making it too heavy to rise.

Another suggestion (thanks bbob) is just covering the pond with a clear material (like plastic or glass) to retain heat. In a high activity (read: kids) area, glass might be broken, but bbobs idea of just floating bubble wrap on it is pure brilliance! And it will keep a little air on the surface of the water under the plastic.

 

Studies 1 with some species of tilapia show that "monoculture" (male only) ponds do not produce significantly higher yields than "mixed" (male and female) ponds.

From The Perfect

Fish http://www.aquanet.com/features/tilapia/perfectfish.htm Since "everyone knows" that female tilapia grow slower than male tilapia, scientists came up with a method of treating all of the tilapia fingerlings with male hormones so those fish that would have been female now turn out to be male. Then all of the fish in the growing tanks or ponds will be male, and the average growth rate will be higher than it would have been with half males and half females. Now even the US government supports the use of reversal techniques by allowing   all of the tilapia hatcheries who wish it to participate in what is known as an INAD. This basically means they have the right to put chemicals into the food of the fish that are not yet cleared as being safe, as long as they send results in to the government.

Almost every tilapia grower now uses hormone-treated fingerling tilapia. This basically reduces the time it takes to get the tilapia through the growing stage and hopefully allows for slightly higher profits from the sale of the fish since a farmer can grow more each year.

The truth is, however, that the only tilapia that grow faster if they are treated with methyl testosterone are the of the "pure line" species. These are produced by breeding, say, males of tilapia nilotica to female tilapia nilotica. If hybrids are produced using t. nilotica and T. aurea or T. mozambique and T. hornorum, any females that are produced will tend to grow as fast as the original male tilapia in the pure line species.

Ocean Rich, Tilapia hatchery and farm in Thermal, California, ph (760)397-7302, fax (760)397-6101Scientific American article by C.F. Hickling, "The Cultivation of Tilapia,"

Also:

See also: