The Urban Aquaculture Manualby Jonathan WoodsSponsored by Heifer Project Internationalwith assistance from theEvangelical Lutheran Church of America

Table Of ContentsChapter One: Urban AquacultureChapter Two: Simple Recirculuation SystemChapter Three: An Aquaponic SystemChapter Four: Resources

Chapter One

URBAN AQUACULTUREINTRODUCTIONAquaculture is a type of animal-based agriculture that can be practiced in smallspaces. It is suitable for city people who want to raise food animals but havelimited space to do it. Unfortunately, there is little information about urbanaquaculture. This manual was written to give city dwellers information aboutaquaculture in the city.This manual provides some basic knowledge about aquaculture. It tells you how tobuild two different aquaculture systems, a simple recalculating system and anaquaponic system. It also tells you how to maintain these systems and what to do ifsomething goes wrong. Finally, it list", some good places to find out more aboutaquaculture.

PROS AND CONSRaising fish in the city is not for everyone. To get good growth, fish have to be feddaily, and something goes wrong with their tank it needs to be fixed promptly.

Here are some of the advantages and disadvantages of using the systems in thismanual.Advantages1. You can raise fish and plants in a small amount of space.2. You don't need a large garden plot or backyard.3. Fresh fish are a nutritious and healthy food.4. Food fish are often cheaper to raise yourself than to buy.Disadvantages1. Tanks take up space and are very heavy.2. Tanks have to be kept warm if you intend to use them over the winter.3. Indoors, an aquaculture system can make a room very humid.4. Some fish can be tricky to raise.

COSTSThere are two types of costs to think about when you decide to build a system,construction costs and maintenance costs. You only have to pay construction costsonce - when you build the system. Maintenance costs include things like food,electricity, and repairs. These are paid for as long as you have the system.Estimates for construction costs (below) and maintenance costs (opposite page) forthe two different systems are shown. By 'crop' I mean the time to raise and harvesta group of fish from fingerling to eating size.

Note that some of the materials that you need can be obtained for free or at a lowprice. These estimates are based on buying most material new at a large hardwarestore like Home Depot. Your costs might be higher or lower than these dependingon where you show, and how much you can get for cheap or free.

BENEFITS

The reason that you are thinking about building a system is because of the benefitsyou will get. Fresh fish and vegetables, satisfaction from growing your own food,and even improved indoor air quality are all benefits that people have gotten fromthese systems. Below, I have show the dollar value of fish and vegetable yields thatyou can expect from a well- run system.

THE BOTTOM LINEThe value of the fish and plants that you grow is higher if you eat them yourself.This is because farmers can get paid a lot less for a crop than consumers pay for itin the grocery store. By eating what you grow, or sharing or trading it withneighbors, you will get higher economic benefits.For each dollar that you spend in food, maintenance and utilities, you can expect toharvest $1.75 to $2.00 worth of fish. If you also are growing vegetables in theaquaponic system, then you will harvest $1.25 worth of vegetables as well. Thetotal return per dollar is close to three dollars for the aquaponic system and twodollars for the simple recirculating system.If you operate your system all year round, then you can recover the cost ofconstruction in one to two years. Operating it only in the summer will lengthen thisperiod to 3 or more years. So if you are planning to use one of these systems formore than 2 years, then it is worthwhile economically to build one.If you feel entrepreneurial, you might consider building more or larger systems andselling your produce.Running small businesses and operating large aquaculture tank systems are beyondthe scope of this manual, but there are some references listed in the ResourcesChapter that you could consult if you want to grow fish and vegetables for profit.

HOW TO STARTThe first thing you should do is read this manual through. This will help you get anoverview of what is involved, what you will have to do, and what you can expect.

Then go and get information or experience from other sources. is there somebodyin your neighborhood who keeps tropical fish? They should be a good source ofinformation.Public libraries are also excellent places to find out more.While you are learning about aquaculture from books and people, keep your eyesopen for sources of cheap or free materials. You can save some money by spendingtime stockpiling things like barrels, pipe, and rocks.

ASK YOURSELF THREE QUESTIONS

Before you start building anything you should ask yourself a few basic questions.These will help you focus on what aquaculture is about and how you really feelabout it.1. Most importantly, do you like to eat fish? What about tilapia? It might be a goodidea to buy a tilapla from a store and eat it, just to make sure that you like the taste.Remember that fresh fish that you raise yourself will taste better than frozen ordead ones from the store.2. Are you (or somebody else who is going to be around to responsible feed andtake care of the system? While you can leave these systems unattended for a fewdays, it is better if somebody is taking care of the fish on a daily basis. Things cango wrong quite quickly with fish, and aquaculturists who check their fishfrequently tend to be successful.3. Finally, why were you thinking about raising fish in the first place? If it was toget rich quick, you may want to reconsider. You won't become rich raising fish 'inbarrels 'in your basement, unless they are rare tropical fish and you are an expert. Ifyou want to raise fish so that you can grow your own food, near your own home,even in the city, then I think that's fantastic and encourage you to try it!

CONCLUSIONRaising fish in small aquaculture systems is a good way for city dwellers andpeople with limited space to raise animals for food. By considering the economiccosts and benefits, and asking yourself what your motivations are, you candetermine whether or not urban aquaculture Is a good idea for you.

Chapter Two

A Simple Recirculation System

INTRODUCTION

This chapter describes how to build a simple, inexpensive and compact aquaculture system. Itfits Into a four foot by four foot space, runs off of one double-outlet air pump, and is easy tomaintain. This is an ideal system to learn about aquaculture without spending a lot of money.The system described in this chapter has been built by ordinary people living in Toronto,Chicago, Little Rock, and Milwaukee. They didn't know much about aquaculture or evenplumbing, but they shared a willigness to try something new and were successful.

HOW THE SYSTEM WORKSThe following is a quick account of the processes that occur in this recirculating system. Lookfor sources of additional information about how such systems work in the Resources Chapter.This system mimics natural cycles. The sun (or artificial light) shines into the plant tank, causingaquatic plants and algae to grow These plants and algae flow into the fish tank (or are cut andfed) where herbivorous fish cat them. After digestion, the fish excrete ammonia (a sort of urine)and produce feces. These are partially broken down by snails and other invertebrates in thebottom of the fish tank and then pumped 'into the b1ofilter tank.

In the biofilter tank, specialized bacteria break down toxic ammonia into fairly harmlessnitrates, which can be taken up by plants. Other bacteria and micro-organisms break down otherwaste products into forms that plants can use. Particles of waste are trapped by rocks and shellswhere they are eaten by invertebrates or broken down by other microorganisms. This tank actslike an aquatic compost pile, converting wastes into fertilizer for the plants.

Finally, the fertilized water flows into the plant tank, where it is taken up and converted intoplant tissues. Submerged plants and algae add oxygen to the water when the sun shines. Cleanwater, oxygen, and green plant food flow into the fish tank, completing the cycle.

SITE

This system should be located in a warm sunny spot with a water source and drain nearby. Itshould sit on a strong floor that is level, and should be protected from vandalism and curioushands.

It is very important that the system is level. If not, the air-lift pumping system will not work well.Most houses and buildings are built with level floors - test the floor with a level or put a marbledown and see if It rolls. If working on bare ground, try to tamp the earth down with a boardwhere the system will go. This will prevent compression and uneven settling. A good idea is toput the system on top of a piece of plywood or a pallet.

PARTS AND TOOLS NEEDED

Hardware

3 - 55 gallon plastic barrels. These should he food grade (i.e , no chemical residues) and at leastone should be semi-transparent.1 - 10' long piece of 2" PVC pipe.6 - 2" male adapters.

6 - 2" female adapters.

3 - 2" tee (T) fittings.

3 - 2" L fittings.

1- aquarium air pump with double air outlet. Get a medium-sized one (e.g. the Elite 802 whichproduces 2500 cc/min. of air at 4.0 PSI)

2 - aquarium air stones.1 - 10' long piece of aquarium air tubing (1/4" clear polyethylene).

several clean rags.1 small can of PVC primer.1 small can of PVC cement.1 roll Teflon (plumbers) tape.1 - tube of clear silicon sealant (bathroom or aquarium grade). Be sure that it is true siliconsealant, as synthetic sealants can be toxic.several small pieces of window screen, preferably plastic, to cover pipes and prevent fish fromescaping2 - strong elastic bands.40 gallons of crushed rock, brick, gravel, or other coarse rock-like material, washed to removedirt and pollution. The pieces should range In size from 1/2" to several inches in diameter. Try toavoid pieces smaller than 1/2".1 - 2' by 2' square piece of burlap or other strong, coarse cloth10 gallons of oyster shells or dolomite, making sure that most of the pieces are larger than 1/2".

Tools

saw - to remove tops from the barrels and cut pipe. A Skill Saw (or "Jigsaw")is probably the best for removing the tops, but a hand saw works well for cutting pipe.

scrub brush or sponge for cleaning up barrels and pipesandpaper or a small file for removing burrs from cut edgesfelt pen to mark the barrels and pipe for cuts

power drill for drilling through-hulls

1/4" drill bit for making holes in filter in Pipe

2 1/4" hole saw (large bore drill bit) to drill holes for through hulls

caulking gun

2 pipe wrenches or large pliers - for tightening through-hulls (optional)scissors - to cut plastic screen and burlap

Biological Materialsbuckets of water (with some bottom mud or sand) from local lakes, rivers or ponds1 quart of fresh compost1 quart of good garden soil1 quart of soil from a forest

1 quart of soil from a meadow20-30 snails from an aquarium store or local pondfloating plants such as water lettuce or water hyacinth20 - 30 fish fingerlings (nile tiapla are recommended)

CONSTRUCTION PROCEDUREMost of this system can be built in two days if you can get all the materials together. Washingand leaching the barrels takes several days to do properly, so plan to do this before the actualconstruction. It is a good idea to let the system stabilize for a few days before adding any fish,so arrange for the fingerlings to be delivered a week or so after you are finished building. Be sureto read ALL the instructions CAREFULLY before starting to build so that you know what has tobe done next.

STEP 1. Rinsing the barrels.You can obtain empty 200-litre food grade polyethylene barrels from food factories, breweries,recycyling centers, and many other places. Big cities often have dealers who buy and sell usedbarrels, or you could call your local recycyling organization. Rinse out the three barrels with agarden hose. Even food-grade barrels could contain toxins, so you should always handle themwith care. Wear gloves, long sleeved shirts, long pants, and safety glasses when rinsing. You candrain them by tipping them over (hard) or using a sipihon (easier).

STEP 2. Leaching the barrels.Leach the barrels. Barrels can be leached by filling them with water, letting them sit overnight,and then draining them the next day. Do this several times, using hot water if available. This willdraw out any rest 'dues that have been absorbed by the plastic and may be harmful to fish.

STEP 3. Cutting the lids out of the barrels.Cut out the lids of the barrels, leaving the rim intact. The rim provides support for the barrel, so itIs important not to cut it off There are several ways of cutting the lid out, depending on whattools you have. You can drill a small hole and then use a skill saw, or you can drill holes all theway around if you don't have a saw.

STEP 4. Washing the barrels.Wash the barrels. Use soap, warm water, and a scrub brush or sponge. You should wear rubbergloves to protect your hands as well as a long sleeved shirt. You could use a mop, or take thebarrel to a commercial car wash where you can use their pressure washer. Rinse off the soap, re-

fill with water, and let them leach overnight again.

STEP 5. Placing the barrels and marking the through-hulls.Arrange the barrels into a triangle on the site you have chosen. Using the felt pen, mark eachbarrel at the point where it is closest to the other two. Now measure six inches (6") straight downfrom each point and draw a cross mark. This will be where you drill the- holes for the connectingpipes.Each barrel should have two crosses. Double check your measurements by measuring from thecross mark to the floor. All the cross marks should be the same distance from the floor.Put the barrels back into the original triangle. Eyeball the crosses to make with sure they line up.Water will not practice circulate well if the crosses are not at quite the, same level.

STEP 6. Drilling the through-hulls.Check the 2 1/4" large-bore drill bit against a male adapter. The bit should be slightly narrowerthan the threads of the adapter. That way the adapter can be screwed into the hole you drill,ensuring a snug fit. Straddle the barrel like youíre riding a horse, or get somebody else to.Carefully drill a hole, using the cross mark center. Remember to hold the drill straight up anddown and lower it slowly. Bracing the drill with your other hand will help you cut an even, cleanhole.

You can practice drilling holes through the lids you removed in STEP 3. Even if you are handy adrill, it is still a good idea to drilling because plastic drills differently from wood.

STEP 7. Connector pipe assembly.Make the connector pipes by cutting three 3" long pieces of 2" pipe. Try to cut the pipe as squareas possible. Use a knife and some sandpaper tosmooth the cut edges. Dry fit (i.e. put together without using cement) a connector piece of pipebetween two male adapters. You should be able to see a little bit of the pipe in between theadapters when it is pushed into them as far as possible. Make two more sets from the remaining3" long pieces of pipe and the male adapters.

STEP 8. Through-hull assembly.Assemble the through-hull fitting as follows. First dry fit a male adapter through each hole, fromthe outside of the barrel in. Then GENTLY screw a female adapter onto each male adapter, butdo not tighten at this point.Put the other two connector pipes together by screwing them into the other two sets of holes.GENTLY screw on some female adapters. At this point, all the barrels in your system should beconnected together 'in a triangle.Now that all the pipe connectors and through-hulls have been put together, have a close look atthe barrels. The barrels should be close together and level, and the three connectors should not bebent at funny angles or appear to be under stress. Check that the system is as you want it beforeyou start cementing it together in the next step

STEP 9. Cementing the connector pipes.WARNING: Primer and cement are dangerous chemicals. You shouldalways wear rubber gloves and work in a well- ventilated area when using 'these chemicals. Be sure to read the ALL safety instructions on the cansbefore opening them!Disassemble one of the connector pipes by unscrewing the male and femaleadapters and removing the connector pipe from between the two maleadapters. You should have two male adapters, two female adapters and a 3"long piece of 2" pipe. Using a rag, wipe clean the inner surface of one of themale adapters and the outer surface of one end of the 3" long piece of pipe.Apply primer to all these surfaces and allow to dry.Working quickly, apply PVC cement to the inside of the male adapters andthe corresponding surface of the 3" long piece of pipe. Twist the pipe andthe adapter together, making sure that you have pushed the pipe in as faras it will go. Wait for a few 11-11inutes until this joint sets, then cement theother male adapter to the other end of the connector pipe. Repeat thisprocedure for the other two sets of connector pipes and male adapters.Allow the cement to dry for 20 minutes before moving on to the next step.

STEP 10. Silicon sealing the through- hulls.Silicon sealant can produce irritating fumes when used indoors. Be sure toventilate your workspace as much as possible. Also, you should try not toget it on your skin or clothes, as it is very difficult to remove.

Take one of the connector pipe/male adapter sets that you made in STEP 9and wrap several layers of Teflon tape around the threads of one of theadapters. Be sure to wrap the tape clockwise around the threads, otherwiseit will bunch up. Generously cover the tape and threads with silicon sealantand twist the adapter through the hole in the barrel. Squirt a bit of silicon'into the female adapter and begin to screw it onto the male adapter frominside the barrel. As you tighten, it will become harder and harder to turnthe adapter and silicon will start to squeeze out from between the male andfemale adapters. Put on some work gloves to protect your hands and tightenthe joint as much as you can. If you have a couple of pipe wrenches, thenuse them to make the joint as tight as possible. Grab one adapter with eachwrench and turn the two wrenches in opposite directions. It is important thata generous amount of silicon gets squeezed out between the adapters by theforce of tightening, as this makes the joint waterproof.Repeat this process for the other five male adapters to female adapterjoints. By the end of this step all three barrels will be joined together bywaterproof connector pipes.Let the silicon dry for 24 hours before moving on to the next step.

STEP 11. Assembling the up-pipes.Cut a 20" long piece and two 3" long pieces of 2" pipe for the plant tank.Cut another set (one 20" piece, two 3" pieces) for the fish tank. Use teefittings to install them into two of the barrels as shown the diagram. Becausethe fittings and pipe are inside the tanks, they do not need to be heldtogether with cement or silicon sealant.Remember that the water has to enter a tank at the top, flow to the bottom,and then go up an up-pipe to exit that tank and enter the next. Therefore, Itis important that you arrange the up-pipes correctly. When set up correctly,only one up-pipe should be attached to each connector pipe assembly.

STEP 12. Assembling the filter pipe.Cut two 3" long pieces of 2" pipe. Install these into the third, empty barrel.Now carefully measure and cut an up-pipe of 2" pipe for the filter tank. It isimportant that the intake lies flat on the bottom, so carefully measure thedistance between the tee fitting at the top and the el fitting at the bottom.Using three more el fittings, cut short pieces of 2" Pipe to make the intakepipe as shown. You may need to trim these pipes to make them fit.Once you have figured out how the filter assembly will fit, disassemble it andperforate the pipe by drilling º" holes approximately 1" apart over the entiresurface of the intake. This will allow water to enter the up-pipe withoutcompromising the strength of the pipe. Reassemble the perforated pipe andinstall into the filter tank.

STEP 13. Final positioning.Before- you put anything heavy into the tanks (like water or rocks) youshould make sure that the tank is properly positioned. The plant tank shouldbe in the sunniest spot. The entire system should be level. If you don't havea level, you can use a bowl full of water on a long straight board instead. Ifyou are placing the system on gravel or on loose soil, you should positionthe whole system on top of a 4'by 4' piece of plywood or a large, sturdypallet. This will prevent the system from settling unevenly

STEP 14. Filling the filter tank.If you are building this system inside a budding, you should consider howheavy it will be and whether the floor will support it. The floors of mostmodern buildings will easily hold the weight of this system. If your buildingis old, and you are unsure about the strength of your floor, you shouldconsult a professional engineer. They will be able to tell you if yourfloor can support a weight of 150 to 200 pounds per square foot.Carefully fill the filter tank with the cleaned fill. "Cleaned fill" means thingslike crushed brick, rock pieces, large gravel, or other rock-like materials thatare free of broken glass, metals, and other contaminants. Be sure tocarefully rinse off any dust or mud, as this will cloud the water.Place the fill piece by piece into the filter tank. You should try to put largerpieces in the bottom, adding medium and pieces as you get near the top.When filling around the filter pipe, try to place the fill so that 'it doesn't restdirectly on the pipe.When the filter tank is three-quarters full, lay the sheet of burlap or filtercloth over the fill. The rest of the tank should be filled with calciumcarbonate materials such as shells or dolomite chips.

STEP 15. Rinsing and leaching the system.Fill the system with water from a hose. If the fill is dirty, then it will cloudthe water with sediment. You may need to fill and drain the tanks severaltimes in order to clear the water. When the water appears fairly clean, fillthe system and let it leach for 24 hours. Drain the tanks and fill them again.

STEP 16. Inoculation.Inoculate the tanks with biological materials. Sprinkle the compost and soilsonto the top of the filter tank. Add the pond/stream/river water to in theother two tanks. Sprinkle snails into all three tanks. Two or threetablespoons of rotten milk can be added to the filter tank to encourage ahealthy microbial community.There are several places where aquatic plants can be added to your system.Emergent plants, such as watercress, can be planted directly into the filtertank. Floating plants, like water hyacinth, can be put on the top of e fishtank or the plant tank. If your plant tank is fairly translucent, submergedplants can be planted on the bottom of the plant tank, but try not to blockthe up-pipe intake.

STEP 17. Installing the airlift pump.

Attach an air stone to a five-foot long piece of air tubing. Lower the air stoneinto the up-pipe of the fish tank, almost to the bottom of the pipe. Plug theother end of the air tubing into the air pump and Plug it in. Push it down asfar as it will go without causing any bubbles to escape from the bottom ofthe pipe. You should see water moving as the air water mixture rises in thepipe and is forced into the next barrel.The airlift is all that is required to circulate water in this system. The systemworks best when the water level half fills the connector pipes, so adjust thewater level by adding or removing some water.The other air stone and tubing should be suspended 'in the fish tank. Thisprovides oxygen to the fish. You will have to weigh it down with a brick orrock. Remember to place the air pump above the system in order to preventit from being flooded.

STEP 18. Preparing the system for fish.You should let the system run without fish for a few days, so the variousmicro-organisms have time to stabilize. This also allows any chlorine thatmay be present in the water to be released into the atmosphere.Chlorine is found in tap water and is toxic to most fish, so you should let tapwater sit for 24 hours before using in any case.Before introducing any fish, block off the entrance and exit of the fish tankwith '/4" mesh or smaller to prevent them from escaping into the filter orplant tank. The mesh can be held on by elastic bands for easy cleaning.If you are planning on keeping fish that require high temperatures (e.g.Tilapia), you will have to install a submersible heater 'in the system or putthe system in a hot place such as a heated greenhouse. Because the systemcontains a lot of water, it will take a day or two for the water to warm up tothe desired temperature.

STEP 19. Adding the fish.You have to introduce the fish slowly to prevent them from being toostressed. If the fish came in a bag, open the top to allow oxygen to enter.Float the bag in the fish tank for an hour or so to allow the water inside thebag to come to the same temperature as the tank. You can hang the openbag from the tee fitting so that the fish don't swim out. Once thetemperature is the same, add a little bit of water from the fish tank into the

bag. Five minutes later, add a little bit more. Do this a few more times, thenslowly tilt the bag underwater so that the fish can swim out of the bag andinto the tank.

STEP 20. The first few days.It is a good idea to cover the tank after first introducing the fish becausesometimes fish will try to escape from a new tank. After a few days, the fishwill become accustomed to their new tank and a cover will no longer benecessary.When fish are first moved, they may not be as hungry due to stress. Feedthem only a little bit at first, gradually increasing the amount of food as theybecome accustomed to their new environment.If all your fish die in the first few days, then something is wrong with yoursystem, with the fish, or something happened during transit. Call the personyou got- your fish from and try to figure out what the problem could be.Usually, you can get replacement fish at a discount if you can convince thefish supplier that there was something wrong at their end.MAINTENANCE

Regular maintenance helps keep a system healthy by spotting smallproblems before they become big problems. The regular tasks that you needto perform are listed according to how frequently they need to be done.

Daily Tasks1. Feed the fish. You can feed fish until they stop eating, or feed them a setamount. Calculating the exact amount of feed to provide is quitecomplicated, so I suggest feeding them until they stop eating on a dailybasis. It is important to watch your fish eat. If they aren't eating happilythen there may be something wrong.2. Check that the water level half fills the connector pipes and add water ifnecessary.3. Check to make sure screens over the inlets and outlets aren't clogged.4. Check the air stone to make sure that it isn't clogged and that the airpump is functioning properly. Clean or replace the air stone whenappropriate.5. Look at the fish to see if they seem healthy.

Weekly Tasks1. Harvest excess plant materials feed to fish or put into compost.2. Check sediment levels at the bottom of the fish tank. They should not bebuilding up but rather be removed by the airlift pump. If they have built up,use a siphon to remove any excess.3. Check ammonia levels. There are numerous kits to measure ammoniaavailable at aquarium stores - read the directions carefully. If ammonialevels are too high, cut back on feed and/or increase aeration (i.e. addanother air stone to the fish tank.) .

Monthly Tasks1. Harvest and restock fish, if required.

2. Remove 10 or 15 gallons of water from the system and replace with waterthat has sat overnight to let chlorine escape. Chlorine is present in all tapwater and can kill or harm fish. By letting it sit in a bucket overnight, mostof the chlorine will escape into the atmosphere as gas. It is a good idea toalways let water that you Intend to use with fish sit overnight.Use any water that you remove from the system in a garden. It is anexcellent liquid fertilizer.

Yearly Tasks1. Remove oyster shell/dolomite layer and rinse. Remove the filter cloth andrinse out any clogged sediment.

CONCLUSION

You are now the proud owner of a recirculating aquaculture system with live,happy fish in it. Congratulations! You should read the Maintenance chapterto find out what you should be doing to keep your fish and your systemalive, growing and happy.

Chapter Three

An Aquaponic System

INTRODUCTION

Aquaponics is the combination of aquaculture and hydroponics. While algae, submerged plants,and floating plants do a good job of removing fish wastes from a recirculating aquaculturesystem, so can lettuce, basil, or many other common vegetables and herbs. Fish wastes can betreated with a biofilter and then allowed to pass through hydroponic troughs, where the roots ofcultivated plants can remove the wastes as fertilizer.In this system, fish are fed in the fish tank. Their wastes are pumped with an airlift pump into abiofilter pipe. This pipe is a smaller version of the biofilter tank used in the recirculating system.As waste-filled water seeps through the biofilter pipe, bacteria and other micro- organismsbreakdown and convert the wastes into forms that plants can use as fertilizer.

At the end of the biofilter pipe, the water spills out through an irrigation bar which distributes thefertilizer- filled water into the two hydroponic troughs. As the water slowly flows along thebottom of the hydroponic troughs, plants in pots draw water and nutrients from the passing flow.Small plants and seedlings are watered through the wicking action of wicking materials in thebottom of their pots. Larger plants grow roots out of the bottom of their pots and into tile flow,soaking tip lots of water and fertilizer.After passing through the biofilter pipe and the hydroponic troughs, the cleaned water tricklesback into the fish tank, where the cycle starts once again.This chapter shows you how to build a simple aquaponic system that will produce both fish andvegetables. Like the simple recirculating system in chapter two, it runs off of one double-outletair pump. This design takes up a four foot by nine foot space but can be made smaller if space islimited.

SITEThis system needs more light than the simple recirculating system, because vegetable crops tendto need more light than water plants. A greenhouse, bright south-facing window, or protectedoutdoor location is best.If, you want to put it inside, you'll need to use lights to grow your plants.This system weighs less than the simple recirculating system, but you should get an engineer tolook at any floor you think may not be strong enough. There are no through-hull fittings in thissystem, and as long as the hydroponic tray is higher than the fish tank it can be put just aboutanywhere. For example, you could put the hydroponic tray on top of an old table with the fishtank on the floor at one end.

PARTS AND TOOLS NEEDEDHardware

1- 50 gallon plastic barrel - preferably food grade and semi-transparent1 - 10' long 1/2" PVC pipe1 - 1/2" PVC male adapter

2 - 1/2" PVC tee fittings1 - 10' long 4" PVC pipe

1 - 4" end cap

1 - 4" "L" fitting

1 - aquarium air pump with double outlet2 - air stones10' of air stone tubing

1 - 4' x 8' board, 1/4" or thicker3 - 1" x 4" boards, 8' long2 - 1 " x 2" boards, 8' long50 - 1" nailsWhite or carpenter's glue for bonding the boards together1 - 6' by 10' piece of polyethylene vapor barrier (6mil is best). This is simply a thick plastic sheetused to protect houses from moisture and can be found in most hardware stores.Staples for staple gun (if using)5 gallons of oyster shells or dolomitePlastic pots for plantsBag of potting soilBag of perlite, vermiculite, cocofiber, or peat moss

ToolsSaw - to remove tops of barrels, cut boards and cut pipeHammerStaple gun (optional - see STEP 9)Felt pen - to mark cutsPower drill3/4" hole saw (or large bore drill bit)Scissors - to cut plastic

Biological MaterialsBuckets of water from local lakes, rivers or pondsA handful of fresh compostA handful of good garden soilA handful of soil from a forestA handful of soil from a meadowSome snails from an aquarium store or local pondVegetable and herb seeds and seedlings20 - 30 fish fingerlings (Nile tilapia are recommended)

CONSTRUCTION PROCEDUREThis system takes a day to build if you can get all the materials together and wash and leach thebarrels beforehand.It is a good idea to add the plants a week or so before adding the fish, so that their roots can growinto the water. Add the fish after the system has stabilized for a week or two. Be sure to readALL the Instructions CAREFULLY before starting to build so that you won't be surprised bywhat comes next.

STEP 1. Rinsing the barrel.Rinse out the barrel with a garden hose. Barrels often contain nasty toxins and should always behandled with care. Wear gloves, long sleeved shirts, long pants, and safety glasses when rinsing.

STEP 2. Leaching the barrel.

The barrel can be leached by filling with water, letting it sit overnight, and then draining the nextday. Do this several times, using hot water if available. This will draw out any toxins that are inthe plastic itself.

STEP 3. Cutting the lid out of the barrel.Cut the lid out of the barrel as shown. Leave the rim intact, as it provides support for the barrel,and be sure to leave a small flap to hold the airlift pump. There are several ways of cutting the lidout, depending on what tools you have available. For example, you could drill a small hole andthen use a skill saw, or you can drill holes all the way around if you don't have a saw.

STEP 4. Washing the barrel.Wash the barrel. Use soap, warm water, and a scrub brush or sponge. Or take the barrel to acommercial car wash. Rinse off the soap, re-fill, and let the barrel leach overnight again.

STEP 5. Making the hydroponic trough.The hydroponic trough is basically a box lined with plastic. A plan for a four by eight-footdouble trough is shown. You can make the trough longer, shorter, narrower, or wider, if youwish. The important thing is that the drains are spaced so that they drain directly into the fishtank, and that there is a space to hold the biofilter pipe.Cut one of the 1'x4" boards into a 46 1/2 " piece and two 16" pieces. Glue and nail the other two8' long 1" x 4" boards onto the long sides of the 4' x 8' board. Glue and nail the 461/2" piece ontoone end of the 4' x 8' board, and glue and nail the 16" pieces to the other end as shown.Find the center of the 4' x 8' board at-id mark it with a pencil. Mark a line 2 1/4" from the centerline on both sides of the center line. Glue and nail the two 1 x 2" boards so that their inside edgeruns along the 2 1/4" lines. You should end up with a 4 1/2-" wide trench in between the two 1" x2" boards, where the biofilter pipe will sit.Using sandpaper, go over the inside of your trough carefully, looking for sharp edges andsplinters that might poke through the plastic. Also look to see if any nails have come through thatmight tear the plastic.

\

STEP 6. Building the irrigation bar.Drill a 1/4" hole through the 4" endcap, as shown. Be very careful to drill this hole straight orelse the joint will leak. Use the caulking gun to cover the threads of a 1/2" male adapter withsilicon sealant. Using a wrench, carefully screw the adapter into the 3/4" hole. Be sure that itgoes in straight. You should be able to screw it until it is flush with the surface of the end cap.Cut two pieces Of 1/2" pipe 1 foot long. Cut one piece 1 inch long. Clean the cut edges withsandpaper and then push the pipe together as shown.

STEP 7. Building the biofilter pipe.If your trough is eight feet long, then cut your 4" pipe to be nine feet long (i.e. cut one foot offthe end). The pipe should be 1 foot longer than the trough. Being careful not to bump the newlyattached irrigation bar, twist the end cap onto one end of the 4" pipe.Carefully rinse the oyster shells or dolomite. The smallest pieces should be no smaller than '/4"diameter, to prevent the biofilter from getting too clogged. Scoop the oyster shells or dolomiteinto the biofilter pipe until it is 90% full. Attach the 4" "L" fitting and set the biofilter pipe aside.

STEP 8. Assembling the system.The system needs to sit on top of something. Pallets, saw-horses, or concrete blocks could Al beused to support the hydroponic troughs off of the ground. The end of the hydroponic troughsnearest to the barrel should be just slightly higher than the lip of the barrel, and the far end aninch or so higher than that. The lip of the barrel should be about 36", so you need to findsupports that will hold the troughs 36" to 38" off the ground.Once you have set up supports for the troughs, set the trough onto them and secure with nails. Ifyou are using cement blocks as a support, you may need to use rope or cord to hold the troughs'in place.Place the barrel under the draining end of the troughs. It should just barely fit beneath thetroughs, and the two drains should hang well over the open top.

STEP 9. Lining the troughsCheck for sharp or rough edges in the troughs one last time. Lay the plastic over the hydroponictrough and begin fitting it into the troughs. Be sure to allow enough slack in the corners so thatthe plastic won't have to stretch when you put plants on top of it. The central trough, where thebiofilter pipe will lie, is lined 'in case of overflows or blockages in the pipe. If the pipe overflowsor breaks, the water will simply flow back into the fish tank.Once the plastic has been fitted, secure it by using a staple gun, home- made pipe-clips' or binderclips from an office supply store. Although harder to make and use, 'pipe-clips' will last longerbecause they won't rust.

STEP 10. Placing the biofilter pipe.Carefully lay the biofilter pipe into the central trough, being careful not to tear the plastic orbreak the irrigation bar.Water flows through the biofilter pipe because the entrance to the pipe is higher than the exit.You can adjust the maximum height of water in the biofilter by twisting the "L" fitting at theentrance. Ideally, the biofilter should be mostly full of water, with a thin layer of air at the top.

STEP 11. Setting up the air-lift pump.Cut a piece of 1/2" pipe 30" long. Drill a 3/4" hole in the middle of the flap that is leftover fromthe barrel lid and insert the 1/2" piece through it. You will probably have to widen the hole alittle bit with a knife. Push the 1/2" tee fitting onto the 30" pipe so that one hole sticks straight upand the other is sideways.Measure the horizontal distance from the tee fitting to the middle of the 4" "L" fitting on the endof the biofilter. The idea is to raise the water up the 30" long pipe, and across to the biofilter. Cut

a piece of pipe to span the distance between the 30" long pipe and the b1ofilter and push it intothe tee fitting. Cut another 6" long piece of 1/2" pipe and push it into the top of the tee fitting.Cut two 5' long pieces of air tubing and hook them up to the outlets of the air pump. Attach anair stone to one of them. Remove the air-lift pipe and drill a ?" hole 4" from the bottom of thepipe. Insert the air tube without any airstone into the hole. You may have to fold it to get itin. Attach a rock to the to the airstone end of the other air tube and let it rest near the bottom ofthe tank. This will provide extra oxygen to the fish.Begin filling the tank with water and turn on the air pump. As the tank becomes full, you will seethe amount of water the air-lift pumps increase. When the tank is full, the air-lift should bepumping a reasonable amount of water into the biofilter, the b1ofilter should fill with water, theirrigation bar will drain into the hydroponic troughs, and the troughs should drain back into thefish tank. Check for leaks, add more water if necessary, and let the system run for 24 hours sothat it can leach. After 24 hours, drain the system, refill, and let run for another 24 hours beforeInoculating.

STEP 12. Inoculation.Inoculate the tanks with biological materials. Sprinkle the handful of compost and soils into theentrance of the b1ofilter. Add the pond/ stream/river water directly to the fish tank, and add afew snails as well. Two or three tablespoons of rotten milk can be added to the b1ofilter tank toencourage a healthy microbial community.

STEP 13. Adding the plants.Half fill the plant pots with peat, cocofibre, vermiculite, or perlite. This layer will wick water upto the plants until their roots grow out of the bottom of the pots. Fill the remaining half of thepots with compost or good potting soil. Plant seeds or seedlings in the pot and arrange them inthe troughs. You should try to place them so that the bottom of the pot touches the water flowingthrough the trough. Water them well with water from the fish tank once you have put them in theplace you want them. Watering them will start the wicking action.You should make sure that the plants you are growing have enough light and the righttemperature. Consult a good hydroponic or gardening book to get this information.

STEP 14. Preparing the system for fish.You should let the system run without fish for a few days, so the various micro-organisms havetime to stabilize and the plants day or two for the water to warm have time to sprout orcompensate for transplant shock. This waiting period is also a good idea as it will allow anyresidual chlorine in the water to escape into the atmosphere. If you are planning on keeping fishthat require high temperatures, you will have to install a submersible heater in the system or putthe system in a hot place such as a heated greenhouse. Because the system contains a lot ofwater, it will take a day or two to warm up to the desired temperature.

STEP 15. Adding the fish.You have to introduce the fish fingerlings slowly to prevent them from being too stressed. If thefish came in a bag, open the top to allow oxygen to enter. Float the bag in the fish tank for anhour or so to allow the water inside the bag to come to the same temperature as the tank. You canhang the open bag from the b1ofilter pipe or the airlift pump so that the fish don't swim out.Once the temperature is the same, add a little bit of water from the fish tank into the bag. Fiveminutes later, add a little bit more. Do this a few more times, then slowly tilt the bag underwaterso that the fish can swim out of the bag and Into the tank.Fish that are delivered in other types of containers should be handled the same way.

STEP 16. The first few days.It is a good idea to cover the tank after first introducing the fish because sometimes fish will tryto escape from a new tank. After a few days, the fish will become accustomed to their new tankand a cover will no longer be necessary.When fish are first moved, they may not be as hungry due to stress. Feed them only a little bit atfirst, gradually increasing the amount of food as they become accustomed to their newenvironment.If all your fish die in the first few days, then something is wrong with your system, with the fishor something happened during transit. Call the person you got your fish from and try to figureout what the problem could be. Usually, you can get replacement fish at a discount if you canconvince the fish supplier that there was something wrong at their end.MAINTENANCE

Regular maintenance helps keep a system healthy by spotting small problems before theybecome big problems. The regular tasks that you need to perform are listed according to howfrequently they need to be done.

Daily Tasks1. Feed the fish. You can feed fish until they stop eating, or feed them a set amount. Calculatingthe exact amount of feed to provide is quite complicated, so I suggest feeding them until theystop eating on a daily basis. It is important to watch your fish eat. If they aren't eating happilythen there may be something Wrong.2. Check that the water level in the fish tank is high enough so that the airlift pump is operatingefficiently.3. Look at the fish to see if they seem healthy.4. Look at your plants to see if they are happy. Check for insect pests, diseases, and nutrientproblems.

Weekly Tasks1. Harvest plant materials and eat. Feed scraps to the fish or put into a compost pile.2. Check sediment levels at the bottom of the fish tank. They should not be building up but ratherbe removed by the airlift pump. If they have built up, use a siphon to remove any excess.3. Check the air stone to make sure that it isn't clogged. Clean or replace when necessary.4. Check ammonia levels. There are numerous kits to measure ammonia available at aquariumstores - read the directions carefully. If ammonia levels are too high, cut back on feed and/ orincrease aeration (i.e. add another air stone to the fish tank.)

Monthly Tasks1. Harvest and restock fish, if required.2. Remove 5 or 10 gallons of water from the system and replace with water that has sat overnightto let chlorine escape. Use the removed water in a garden.3. Check to see if the biofilter pipe is becoming clogged. If It is, remove the el fitting, dump outthe oyster shells or dolomite, rinse, and then replace.

CONCLUSION

You are now an aquaponic farmer, growing happy, healthy fish and vegetables in a recirculatingaquaponic system. Congratulations! You should read the Resources chapter to find out what youshould be doing to keep your fish, your plants, and your system alive, growing, and happy.

Chapter 4Resources

INTRODUCTION

This chapter contains information that should be useful in running yoursystem. The information is arranged according to topic, and each sectionstarts with background material relevant to the tables and lists in thatsection.

FISH FOODS

Some fish are fussy eaters; most fish will eat a wide range of foods, while afew will try just about anything. Garbage in, garbage out is as true for fish

as for humans, but determining exactly what is garbage for a fish is slightlymore difficult than human nutrition. Fish grow faster when there is a lot ofprotein in their diet, although they need their carbohydrates and vitamins aswell. A good food to start with (and an excellent back-up food in any case) isany sort of cheap dog food or trout/catfish chow if you can get it. Anothergood all around food for fish is seaweed or kelp meal. This is especially goodfor baby fish and can be purchased at garden centers or feed mills.

Feeding ideas

1. Fertilization. If you are raising a herbivorous fish, or if the fish you areraisin cats something that grows readily in your system then fertilizing thetank to promote algal (and therefore zooplankton) growth. Compost isprobably the best sort of fertilizer for a small system. Use only a handful ortwo and then wait to see what happens.

2. Food scraps. There are a lot of wasted foods out there, and if you canget your hands on a steady, local supply, you could end up feeding your fishfor free. Tilapia will cat vegetable peelings, as will carp. Many fish will takemeat scraps, fishmeal, or leftovers from the table. There are recipesavailable for homemade fish feeds from waste materials - see the bookFreshwater Aquaculture for a good introduction. Here are some suggestionsof food resources in the city.Stale bread and bakery throwoutsFish scraps - frozen and groundMeat scraps - fresh or frozen and groundVegetable peelingsOld vegetables from marketsRestaurant wet wastes

These can be found at numerous commercial businesses, as well as publicplaces like schools and institutions. If your fish will cat it, you probablyproduce enough food scraps 'in your house to feed a healthy population oftilapia. If you do not have a dog, then a tank full of leftover-eating fish canbe your substitute.

3. Collect invertebrates for food. Most fish love eating insects, especiallylive ones, - and if you know where to look and are not too squeamish, thereare lots of potential insect sources in and around a city. The first one thatcomes to my mind is cockroaches squish 'em and toss them to the sharks!Many of these can be trapped and (for the intrepid) can even be culturedright in your own backyard. Here are some ideas.Earthworms

CockroachesCricketsSnailsSlugsFliesMothsBeetlesBuried beetle and wasp larvaeBig, juicy caterpillars4. Keep a worm bin. Red wigglers are a favorite food of tilapia andalso help you reduce your household wet wastes into nice, indoorcompost. God's Gang, who have several aquacultural ecosystems setup in Chicago, grows red wigglers both for sale and to feed to theirfish. Fish fed with earthworms on a regular basis grow healthy andstrong due to the high vitamin content of these little guys.5. Grow some plants. Fish, especially herbivorous fish, will eat a lot ofplant materials that we do not even consider to be food, Of course, fish willeat just about all the fruits and vegetables that we eat, so these are notlisted here but are also good sources of food. The following list shows someof the more exotic parts of the fish diet.Water hyacinth - fish will not eat it unless you take it out of the tank, chop itup, and then return it to the tankAzollaDuckweedCarrot topsMarigoldsTaro leavesPurslaneGreen tomatoesMuch has been written on feeding fish and the references in the bibliographyshould give you some direction if you are interested in developing new waysof feeding them. Fish will eat so many things that it is always worth tryingsomething new The best way to test a new food is to put a little bit in thetank and watch for awhile. Usually fish will mouth the new food and then spitit out - it is their way of testing. If they do not eat it right away, leave themalone for an hour or so and check again. The food will most likely be gone bythen if they are going to eat it at all. An exception is live foods. Fish seem toknow that a live insect or worm will stay fresh until they eat it (or until itdies), so they often let it live in the tank for a few days before consuming it.This is especially true with worms, who can live underwater if the water iswell oxygenated. Just as they think that they have escaped, the fish usuallyeats them!FISH SPECIES FOR AQUACULTURAL ECOSYSTEMS

I am not an expert in raising many different types of fish, but there are somany experts out there already that you can easily find information aboutthe fish you might want to raise. Table 7-1 lists several fish species, theirtemperature ranges, and whether or not they are easy to raise. The lastcategory was determined from a literature review generally aquacultureauthors agree about which species are easy and which are temperamental.It is interesting to note that many widely farmed fish are actually quitedifficult to raise. The reason that they are widely farmed usually has nothingto do with how easy or hard they are to raise, but rather how much moneythey can make for the farmer, and that is why trout and channel catfish areso popular among North American farmers. In countries where people raisefish for their own or local consumption, carp, Chinese carp, and tilapia aremuch more widely raised.

Good places to go for advice about fish are extension agents, pet stores, fishdealers, and the library. Anybody who sells you fingerlings must know athing or two about how to raise fish, so make sure that some advice isincluded in the purchase price. Take advice with a lot of salt, however. Icannot remember how many people have told me that I was raising fish thewrong way! Usually commercial fish farmers have little knowledge aboutrecirculating systems but they still know a lot about the particular species offish that they raise.

OTHER EDIBLE ANIMALS

There are several other species of animal, mostly invertebrate, that youmight want to try raising as you become proficient. Most of these arecrustaceans, but if you like to eat frogs, why not? All these species arefreshwater types and would be suitable for aquacultural ecosystems,providing you do a little background research on their natural history-Freshwater shrimp (Macrobrachium spp.)

Crayfish (Procambarus spp.)Bullfrog (Rana catesbeiana)Freshwater clamsTurtlesYabbles (an Australian crayfish)Giant snail (Achanita spp.)Escargot (Helix spp.)Freshwater crab (Halicarcinus spp.)

VEGETABLES

These are lists of vegetables (including herbs and annual fruits) that growwell under certain conditions or are tolerant of aquatic conditions. Some ofthe uncommon ones may be difficult to get a hold of in North America butare included here, as you should be able to find them if you look hardenough. Also, some root vegetables have been largely overlooked as theyare difficult (or at least impractical) to grow in aquacultural ecosystems.

Vegetables that float on the water surfaceWater hyacinthWater mimosaWatercressVegetables that grow in underwater soil (emergent vegetables)Water chestnutLotusTaro (Colocasla esculentes)Kangkong (Ipormea aquatica)WatercressIndian water chestnutArrowheadChinese arrowheadWild riceDuck potatoWater celeryManchurian wild riceVegetables that grow well in hydroponicsThese are the basic ones. Almost all-common annual vegetables can begrown hydroponically with the exception of some root vegetables such aspotatoes. See a good magazine like The Growing Edge or look in thebibliography for books about hydroponics.Basil eggplantMint kaleArugula lettuceChives mustard greensCoriander peas

Ginger peppersParsley radishBeans rapiniBok choy spinachBroccoli sweet potatoCabbage tomatoChard zucchiniChinese cabbage cucumberCorn

AQUATIC PLANTS

There are many aquatic plants available both in a good garden center as wellas in the local pond. Increasing the diversity of aquatic plants in your systemwill also increase the diversity of the microorganisms that use aquatic plantsas habitat. Many of them can be quite beautiful, especially if the conditionsare right for them to flower. Also see the vegetable section for plants inthese categories.Floating plantsWater hyacinthWater lettuceDuck-weedSalviniaAzollaIndonesian water hyacinth bladderwort

Submerged plantsHydrillaElodea

Plants that are rooted in underwater soil (emergent plants)CattailAlligatorweedPickerel weedSmartweedLotusWater lilyWater buttercupWatercress

TROUBLESHOOTING

If you maintain a healthy system and do riot overload it with organisms, youshould not encounter any serious problems. Every, system is different andtherefore each system will experience problems in a different way. What Ihave tried to do here is to set up a problem-solving helper based on my

experience of what some of the common problems are. If you come to theend of this helper and the problem is not solved then it is up to you - beresourceful!

To use this helper, simply look down the list of problems until you find onethat sounds like what you are experiencing. There are numbers for solutionslisted below. Sometimes a major problem (like Fish almost Dead) will referyou to a lesser problem (such as Pump is Broken) as problems seem to setthemselves up in a hierarchy. Check each of these possible solutions in orderto see I if they solve your problem. Good luck!

PROBLEMS

System problems(P1) - Water is not circulating / no bubbles. (S1) (S2) (S3) (S4) (S5)(S6)(P2) - Puddles on the floor around the system. (S7) (S15) (P4)(P3) - Big puddle surrounding the system. (S8) (P9) (S15) (S17)(P4) - Found a leak! (S9) (S15)(P5) - Funny smell - rotten eggs. (S10)(P6) - Funny smell - like manure. (S11)(P7) - Funny smell - fishy smelling. (S12) (P11)(P8) - Funny smell - ammonia! (S13) (S12)(P9) - Cracks in the ceiling in room below system. (S14)

Fish problems

(P10) - ALL THE FISH ARE DEAD THIS MORNING! (P1) (P5) (P6) (P7)(P8) (S16) (S17)(P11) - One of the fish is dead, others appear fine. (S18)(P12) - Fish gasping at surface. (P5) (P6) (P7) (P8) (S19)(P13) - One fish is swimming funny, covered with lesions, or does not feedwith the rest. (S18)(P14) - Fish attacking each other. (S22) (S23) (S24) (S16) (P5) (P6)(P7) (P8)(P15)- Some fish seem to be missing. (S7) (S17) (S6) (S25)(P16)- One fish grows really fast, smaller fish missing. (S26) (S25) (S6)(P17) - Fish do not seem to grow (SI6) (S27)(P18) - Fish never get very big, more and more appearing. (S27) (S24)(S16) (S28)(P20)- Fish are not feeding. (S27) (P1)

Plant problems(P21) - Plants appear unhealthy. (S30) (S31) (S32) (S33) (P26)(P22) - Plants do not grow. (S31) (P21)(P23) - Plants grow but are spindly. (S31) (P21)

(P24) - Plants grow well, but no flowers or fruits. (S30) (S31)(P25) - Flowers appear, but no fruits. (S35) (S31)(P26) - Insects, insects, everywhere! (S34)

SOLUTIONS

(S1) - Screens are clogged. These need regular maintenance for smoothoperation. Scrub with a brush to remove accumulated algae and debris. Ifpossible, use a larger mesh size.

(S2) - Air pump broken or not plugged in. Check for air from the outlettube. If there is none then you may have blown a gasket. Buy a replacementgasket (US $2-3) at a pet store.

(S3) - Air tubing is clogged. Remove the air stone and try to blow throughthe tubing with your mouth - you should be able to do this easily and feel aircoming out the other end.

(S4) - Air stone clogged. Air stones get clogged eventually with algae andother stuff They can be cleaned somewhat by soaking 'in vinegar, but willnever bubble as well as a new one. Clean or replace.

(S5) - There is a clog in the plumbing. Visually inspect all plumbing, use astick to probe the depths. Sometimes, a fish gets caught in the plumbingand blocks it up. Snails will sometimes congregate in plumbing to the extentwhere water flow is blocked. Exclude both with some 1/4" mesh. (S6)

(S6) - There is a clog in the b1ofilter. If you make your biofilter too fine, oryou do not use a large enough uptake pipe, you may find that your systemclogs. Also, your biofilter may need a good cleaning. Set aside a few hoursand take apart your b1ofiltcr to find out what the problem is. (S25)

(S7) - Fish like to play. Sometimes newly introduced fish splash aroundwhile they settle into their new environment. Sometimes they jump to theirdeath. Put a net over the fish tank to prevent jumpers.

(S8) - There is a big leak in your system and you had better find it soon.Rescue what you can and try to determine if the leak is repairable. Usually aleak is found at a joint or in the biofilter - check those first.

(S9) - If you can, drain the System to below the level of the leak, let it dryout, and then repair with silicon. It is almost impossible to properly repair aleak while it is wet. Alternate layers of plastic bags and duct tape may do thetrick, temporarily.

(S10) - Toxic hydrogen sulfide is being released! Act fast; provide as muchdissolved oxygen as you can to the afflicted tank. Gently vacuum up anyanaerobically decomposing material from the bottom of the tank. (P1)

(S11) Methane is being produced. Eventually, this can cause problems,especially if other people have to around your system. Gently vacuum upany anaerobically decomposing material from the bottom of the tank. (P1)

(S12) - Food is rotting in the system. Locate and remove any obviouslyrotting pieces of food. Avoid feeding too much.

(S13) - Ammonia is highly toxic, aerate immediately Prevent futureproblems by encouraging nitrifying bacteria in a biofilter. (P1)

(S14) Call an engineer. Your system is too heavy for the building structure -move it to the basement.

(S15) - Leaking water can cause rotting problems with wooden structures.Protect the floor with plastic or move the system.(S16) - Check the water temperature and compare it with recommended

ranges for your fish.(S17) Fish tanks in semi-public places are prone to vandalism. Respondappropriately.(S18) - Remove fish and inspect for signs of disease or attack. Suspiciousspots, missing scales, funny colored eyes, and other symptoms all couldindicate a diseased fish. Alive still - S (20). Dead - S (21).(S19) - Dissolved oxygen is in short supply. Aerate immediately bywhatever means necessary. (P1)(S20) - Keep fish isolated in a well-aerated tank. Feed only sparingly andonly if fish seems willing to eat. (S21)(S21) - Increase aeration and keep a close eye on the rest of the fish.Consult a fish disease handbook and do a biopsy if you feel up to it.(S22) - The attacked fish may be ill. See (S18).(S23) - The attacking fish may be ill. See (S 18).(S24) - The fish may be breeding. Consult natural history information aboutthat species in order to confirm this.(S25) - Sometimes fish escape into other parts of the system. If they haveyou will find them eventually.(S26) - Fish are eating each other. Either come to terms with this horriblefact of life, or choose a less cannibalistic species.Increasing the availability oflive food and reducing population density will reduce cannibalism. You couldalso try removing all the big fish, or removing all the small fish (called"grading").(S27)- There may be a problem with the foods you are giving them. Trysomething different for awhile to see if they improve.

(S28)- Fish may be overcrowded. Increase water circulation and biofiltrationor reduce fish density.(S30)- There is a nutrient deficiency. Check a nutrient table to see if one ofthese matches the symptoms. Nutrient tables can be found in goodgardening books.(S31)- There is not enough light. Move the plants to a place where they canget more light, supplement the available light, or grow more shade-tolerantplants.(S32)- The plants are diseased. Check a plant disease book. Remove anddestroy diseased plants.(S33)- The roots are waterlogged and possible rotting. Evaluate yourgrowing system and consult the hydroponics literature.(S34)- The plants may be infested with detrimental insects. Confirm with aninsect guidebook. Feed infested plants (insects included) to the fish. Look ina good organic gardening book for ideas about controlling futureinfestations.

(S35) There are no pollinators. Open the window or, if it is too cold,investigate artificial pollination techniques.

BIBLIOGRAPHYBooks and ManualsI have in my opinions on the following books, which I have found useful forunderstanding and learning about aquaculture, hydroponics, and agriculturein general. Usually, the most interesting materials are in magazines andjournals, but there is a lot of historical, reference, and background materialin larger books. Older books tend to be interesting and informative - oftenthey contain ideas that were rejected for one or another reason by therather narrowly focused aquaculture/hydroponic industry. Much early workon sustainable and organic methods in these fields was rejected outright ormodified by the industry to conform to sterile, chemical agriculture. Now, assustainable aquaculture and organic hydroponics arc coming into vogue,many of the best books are out of print. A good public library can be a goldmine of useful information from the past.

Chakroff, Marilyn. 1976. Fresh water fish pond culture andmanagement. Volunteers in Technical Assistance (VITA) publication #36E

- The Peace Corps classic. Chakroff wrote this manual from firsthandexperiences while serving in the Philippines with the Peace Corps. Whilethere is little information about tanks, the information about fish, theirbiology, and how to take care of them is accurate and accessible. Mostlibraries seem to have a copy - worth the effort and expense to photocopythis book if you can find it.

Mollison, Bill. 1997. Permaculture -A Designer's Manual Ten-speed Press.Mollison, Bill. 1998. Introduction to Permaculture. Ten-speed Press.

- Bill is one of the most creative agricultural thinkers of this century. All ofhis works 'include sections on aquaculture and the underlying philosophy ofpermaculture is both interesting and useful for anyone who likes tocontemplate our place inthe world. Full of new ideas and practical advice.

McLarney, William. 1998. Fresh water aquaculture. Hartley & Marks, PortRoberts, WA.

- The standard textbook on small-scale, freshwater aquaculture, McClarneywas a founding member of the New Alchemy Institute and worked with JohnTodd 'in his early career. This book was out of print for a long time but the1984 edition has now been reprinted and it is available through specialorder. Lots of information and charts, but a lot of the contact information isout of date and useless. He tries to promote using North American speciesfor aquaculture as opposed to introduced species like carp. I would notrecommend purchasing this book unless you want to raise N. Americanspecies, want more technical information about aquaculture, or areinterested in other forms (such as ponds, lakes, cages, etc.)

Logsdon, G. 1978. Getting food from water. Rodale Press, Emmaus, PAAn excellent but out of print book. Seems that all the alternative agricultureorganizations were running interesting programs on aquaculture andaquaponics in the seventies. Now Rodale publishes magazines like "Men'sHealth" and the New Alchemy Institute is defunct. This book is an excellentalternative to McClarney's text. It Is written in a more accessible style andseems to be more on the scale of home gardeners. There's even an accountof an old man who raises catfish in a bathtub. Out of print but a valuableread if you can find it.

Todd, Nancy Jack and John Todd. 1994. From Eco-cities to Living machines:Principles of ecological design. North Atlantic Books.John Todd and his wife outline their philosophies and ideas about ecologicalengineering and the role of ecology in design. Not a very handsome book,but it does have some interesting ideas about aquaculture, cities, and thefuture of the planet. Generally, while the ideas coming out if the NewAlchemy Institute are pretty cool, the books and other publications from themembers of this group are sort of vague and disappointing. If this groupwants the world to change using its ideas, then they need to write a detailedmanual about building living machines. There are a lot of willing people outthere who are sort of puttering in the dark trying to do good things butapparently missing key details.

DeKorne, James B. 1992. The hydroponic hot house: low-cost, high-yieldgreenhouse gardening. Loompanics Unlimited.

DeKorne is the last of the paranoid survivalists, but has developed somevery useful systems for growing things hydroponically indoors. He is aninventor who has limited resources - the results are accessible, cheap, andeasy to build systems.

Resh, Howard Al. 1 990. Hydroponic home food gardens. Woodbridge Press.

Resh is the dean of commercial hydroponics in North America. Every goodhydroponics store will be stocked with his books, and libraries usually have afew copies. This book is the most accessible of his works, and although theideas are fairly narrow-minded and conventional, at least it provides a solidsurvey of the hydroponic industry in general.

Douglas, James Sholto. 1985. Advanced guide to hydroponics (soillessculture).

Douglas, James Sholto. 1976. Hydroponics: the Bengal system.

- Douglas was one of the first writers about the 'new' science of hydroponicsand he was very keen on organic and sustainable methods of production. Ifyou can find any of his books, snap them up. Reading Douglas after readingResh, you realize that Resh's entire scope would fit into a specialist chapteror two of Douglas' global perspective. Look for these books in the library.

Addey, William and Karen Loveland. 1998. Dynamic Aquaria. AcademicPress.A fantastic book about how aquariums and ecosystems work, written by twobiologists. Full of explanations about how different environmental factors caninfluence fish and other organisms. Also has good ideas about how to stockan aquatic system with plants, fish, and other organisms.

Magazines

Of all the magazines published currently, the Growing Edge is by far themost relevant and useful. It often has articleabout aquaponics and organicmethods, and is an excellent source for latest hydroponic ideas. PracticalHydroponics andGreenhouses from Australia is equivalent to the GrowingEdge in quality and outlook, but can be expensive because it is imported.The out of print Journal of the New Alchemist and the New AlchemyQuarterly have good articles about livingmachines but are rather difficult tofind.A good all-around gardening magazines is Organic Gardening. It is widelyavailable and contains useful information about vegetables, composting, and

the occasional water-gardening/hydroponic/aquaculture article. Older issuesare better than recent issues, as the current editor seems more concernedabout growing ornamentals than food.Aquaculture Magazine the best source for industry news and format. Theirarticles are well written and researched, although keep in mind that thebottom-line is the driving force behind this magazine. Their annual Buyer'sGuide is a must-have. It tells you where to get everything you could possiblyneed for aquaculture, especially sources of fingerlings.All of these magazines have extremely useful back-issues. You can findthese in a good library system or you can often buy them at a discount formthe publisher.Aquaculture MagazineP.O. Box 2329Asheville, NC, 28802USAwww.aquaculturemag.com

The Growing Edge Magazine1-800-888-6785www.growingedge.com

Organic GardeningRodale PressEmmaus, PA, 18049USAwww.organicgardening.com

Practical Hydroponics and GreenhousesP.O. Box 225Narrabeen, NSW2101 Australiawww.hydroponics.net.au

Journal of the New Alchemists, New Alchemy Quarterly - Both are out ofprint. Try contacting Ocean Arks International or your local public library tolocate back issues.Free LiteratureGenerally, your local extension agent will be able to provide you withinformation about some aspects of your proposed project. Here is oneagency that has been particularly helpful.Southern Regional Aquaculture Centerc/o Michael P. Masser106A Swinger HallAuburn University, AL, 36849-5628USA

(334) 844-9312(334) 844-9208 (fax)mmasser@acesg.auburn.edu

This center has put a lot of effort into promoting aquaculture. They have anexcellent range of free publications, many of which are highly useful forrecirculating aquaculture enthusiasts. They are one of the few places whichpromote crayfish, Chinese carps, tilapia, and exotic shrimps in the USDAsystem. They are also excellent sources of information about where to buyless common species. Ask for the following pamphlets in particular.SRAC282 Tank culture of TilapiaSRAC451 Recirculating aquaculture tank production systems. An overview ofcritical considerations.SRAC 452 Recirculating aquaculture tank production systems. Managementof recirculating systems.SRAC 453 Recirculating aquaculture tank production Systems.Component OptionsSRAC 454 Recirculating aquaculture tank production systems. Integratingfish and plant culture.Herb, Frances Raising snails for foodWEB SITES

Web access is becoming more widely available, and even In the developingworld Internet is available at reasonable prices (approx. US$5 per hour) inInternet cafes. There are tons of resources on the Internet but bewareanybody can write Just about anything in cyberspace and nobody checkstheir work. Be wise about advice and ideas that you glean off the Internet -if It sounds too good to be true, it probably is.

The following sites have useful information and will lead you to other sites.www.jeffcook.com/hbpond.htm1Jeff's half -whiskey-barrel page, while not quite as funny as Eric's is also fullof information. He has a lot of different opinions from Eric, but the two endup with the same thing in the end. Jeff 's links are extensive.www.livingmachines.comThe Living Technologies company site. This site is John Todd's consultingsite. There are some interesting photos, information, and links, as well asexamples of how Todd has applied living machines to industrial problems.

ext.msstate.edu/anr/aquacultureAccess to Mississippi State University's excellent collection of aquacultureextension information.www.kloubec.com- A major tilapia producer in Iowa, their site gives a good overview of thisspecies.

ag.arizona.edu/azaqua/tilapia- A large but disorganized site containing lots of information about tilapia.www.itv.se/rainbow- Swedish farmers who grow trout and vegetables in a recirculating system,www.townsqr.com/snsaqua- Home page of the Sperraneo family who are successful aquaponic farmersin Missouri.www.cropking.com/store/AquaM/AquaSystem.htm

◦ A large-scale and high-tech aquaponic system made by a majorhydroponic equipment manufacturer.

keywords to search with for internet informationaquaponicshydroponics and aquacultureliving and machinesaquaculture and recirculatingalternative and aquaculture