This chapter contains information that should be useful in running your system. The information is arranged according to topic, and each section starts with background material relevant to the tables and lists in that section.
Some fish are fussy eaters; most fish will eat a wide range of foods, while a few 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 slightly more difficult than human nutrition. Fish grow faster when there is a lot of protein in their diet, although they need their carbohydrates and vitamins as well. A good food to start with (and an excellent back-up food in any case) is any sort of cheap dog food or trout/catfish chow if you can get it. Another good all around food for fish is seaweed or kelp meal. This is especially good for baby fish and can be purchased at garden centers or feed mills.
1. Fertilization. If you are raising a herbivorous fish, or if the fish you are raisin cats something that grows readily in your system then fertilizing the tank to promote algal (and therefore zooplankton) growth. Compost is probably the best sort of fertilizer for a small system. Use only a handful or two and then wait to see what happens.
2. Food scraps. There are a lot of wasted foods out there, and if you can get your hands on a steady, local supply, you could end up feeding your fish for free. Tilapia will cat vegetable peelings, as will carp. Many fish will take meat scraps, fishmeal, or leftovers from the table. There are recipes available for homemade fish feeds from waste materials - see the book Freshwater Aquaculture for a good introduction. Here are some suggestions of food resources in the city.
Stale bread and bakery throwouts
Fish scraps - frozen and ground
Meat scraps - fresh or frozen and ground
Old vegetables from markets
Restaurant wet wastes
These can be found at numerous commercial businesses, as well as public places like schools and institutions. If your fish will cat it, you probably produce enough food scraps 'in your house to feed a healthy population of tilapia. If you do not have a dog, then a tank full of leftover-eating fish can be your substitute.
3. Collect invertebrates for food. Most fish love eating insects, especially live ones, - and if you know where to look and are not too squeamish, there are lots of potential insect sources in and around a city. The first one that comes 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 cultured right in your own backyard. Here are some ideas.
Buried beetle and wasp larvae
Big, juicy caterpillars
- 4. Keep a worm bin. Red wigglers are a favorite food of tilapia and also help you reduce your household wet wastes into nice, indoor compost. God's Gang, who have several aquacultural ecosystems set up in Chicago, grows red wigglers both for sale and to feed to their fish. Fish fed with earthworms on a regular basis grow healthy and strong due to the high vitamin content of these little guys.
5. Grow some plants. Fish, especially herbivorous fish, will eat a lot of plant materials that we do not even consider to be food, Of course, fish will eat just about all the fruits and vegetables that we eat, so these are not listed here but are also good sources of food. The following list shows some of the more exotic parts of the fish diet.
Water hyacinth - fish will not eat it unless you take it out of the tank, chop it up, and then return it to the tank
Much has been written on feeding fish and the references in the bibliography should give you some direction if you are interested in developing new ways of feeding them. Fish will eat so many things that it is always worth trying something new The best way to test a new food is to put a little bit in the tank and watch for awhile. Usually fish will mouth the new food and then spit it out - it is their way of testing. If they do not eat it right away, leave them alone for an hour or so and check again. The food will most likely be gone by then if they are going to eat it at all. An exception is live foods. Fish seem to know that a live insect or worm will stay fresh until they eat it (or until it dies), 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 is well oxygenated. Just as they think that they have escaped, the fish usually eats them!
FISH SPECIES FOR AQUACULTURAL ECOSYSTEMS
I am not an expert in raising many different types of fish, but there are so many experts out there already that you can easily find information about the fish you might want to raise. Table 7-1 lists several fish species, their temperature ranges, and whether or not they are easy to raise. The last category was determined from a literature review � generally aquaculture authors agree about which species are easy and which are temperamental. It is interesting to note that many widely farmed fish are actually quite difficult to raise. The reason that they are widely farmed usually has nothing to do with how easy or hard they are to raise, but rather how much money they can make for the farmer, and that is why trout and channel catfish are so popular among North American farmers. In countries where people raise fish for their own or local consumption, carp, Chinese carp, and tilapia are much more widely raised.
Good places to go for advice about fish are extension agents, pet stores, fish dealers, and the library. Anybody who sells you fingerlings must know a thing or two about how to raise fish, so make sure that some advice is included in the purchase price. Take advice with a lot of salt, however. I cannot remember how many people have told me that I was raising fish the wrong way! Usually commercial fish farmers have little knowledge about recirculating systems but they still know a lot about the particular species of fish that they raise.
OTHER EDIBLE ANIMALS
There are several other species of animal, mostly invertebrate, that you might want to try raising as you become proficient. Most of these are crustaceans, but if you like to eat frogs, why not? All these species are freshwater 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)
Yabbles (an Australian crayfish)
Giant snail (Achanita spp.)
Escargot (Helix spp.)
Freshwater crab (Halicarcinus spp.)
These are lists of vegetables (including herbs and annual fruits) that grow well under certain conditions or are tolerant of aquatic conditions. Some of the uncommon ones may be difficult to get a hold of in North America but are included here, as you should be able to find them if you look hard enough. Also, some root vegetables have been largely overlooked as they are difficult (or at least impractical) to grow in aquacultural ecosystems.
Vegetables that float on the water surface
Vegetables that grow in underwater soil (emergent vegetables)
Taro (Colocasla esculentes)
Kangkong (Ipormea aquatica)
Indian water chestnut
Manchurian wild rice
Vegetables that grow well in hydroponics
These are the basic ones. Almost all-common annual vegetables can be grown hydroponically with the exception of some root vegetables such as potatoes. See a good magazine like The Growing Edge or look in the bibliography for books about hydroponics.
Chives mustard greens
Bok choy spinach
Broccoli sweet potato
Chinese cabbage cucumber
There are many aquatic plants available both in a good garden center as well as in the local pond. Increasing the diversity of aquatic plants in your system will also increase the diversity of the microorganisms that use aquatic plants as habitat. Many of them can be quite beautiful, especially if the conditions are right for them to flower. Also see the vegetable section for plants in these categories.
Indonesian water hyacinth bladderwort
Plants that are rooted in underwater soil (emergent plants)
If you maintain a healthy system and do riot overload it with organisms, you should not encounter any serious problems. Every, system is different and therefore each system will experience problems in a different way. What I have 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 the end of this helper and the problem is not solved then it is up to you - be resourceful!
To use this helper, simply look down the list of problems until you find one that sounds like what you are experiencing. There are numbers for solutions listed below. Sometimes a major problem (like Fish almost Dead) will refer you to a lesser problem (such as Pump is Broken) as problems seem to set themselves up in a hierarchy. Check each of these possible solutions in order to see I if they solve your problem. Good luck!
(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)
(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 feed with 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)
(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)
(S1) - Screens are clogged. These need regular maintenance for smooth operation. Scrub with a brush to remove accumulated algae and debris. If possible, use a larger mesh size.
(S2) - Air pump broken or not plugged in. Check for air from the outlet tube. If there is none then you may have blown a gasket. Buy a replacement gasket (US $2-3) at a pet store.
(S3) - Air tubing is clogged. Remove the air stone and try to blow through the tubing with your mouth - you should be able to do this easily and feel air coming out the other end.
(S4) - Air stone clogged. Air stones get clogged eventually with algae and other stuff They can be cleaned somewhat by soaking 'in vinegar, but will never bubble as well as a new one. Clean or replace.
(S5) - There is a clog in the plumbing. Visually inspect all plumbing, use a stick to probe the depths. Sometimes, a fish gets caught in the plumbing and blocks it up. Snails will sometimes congregate in plumbing to the extent where 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, or you do not use a large enough uptake pipe, you may find that your system clogs. Also, your biofilter may need a good cleaning. Set aside a few hours and take apart your b1ofiltcr to find out what the problem is. (S25)
(S7) - Fish like to play. Sometimes newly introduced fish splash around while they settle into their new environment. Sometimes they jump to their death. 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 a leak 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 dry out, and then repair with silicon. It is almost impossible to properly repair a leak while it is wet. Alternate layers of plastic bags and duct tape may do the trick, temporarily.
(S10) - Toxic hydrogen sulfide is being released! Act fast; provide as much dissolved oxygen as you can to the afflicted tank. Gently vacuum up any anaerobically 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 up any anaerobically decomposing material from the bottom of the tank. (P1)
(S12) - Food is rotting in the system. Locate and remove any obviously rotting pieces of food. Avoid feeding too much.
(S13) - Ammonia is highly toxic, aerate immediately Prevent future problems 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. Respond appropriately.
(S18) - Remove fish and inspect for signs of disease or attack. Suspicious spots, missing scales, funny colored eyes, and other symptoms all could indicate a diseased fish. Alive still - S (20). Dead - S (21).
(S19) - Dissolved oxygen is in short supply. Aerate immediately by whatever means necessary. (P1)
(S20) - Keep fish isolated in a well-aerated tank. Feed only sparingly and only 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 about that species in order to confirm this.
(S25) - Sometimes fish escape into other parts of the system. If they have you will find them eventually.
(S26) - Fish are eating each other. Either come to terms with this horrible fact of life, or choose a less cannibalistic species. Increasing the availability of live food and reducing population density will reduce cannibalism. You could also 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. Try something different for awhile to see if they improve.
(S28)- Fish may be overcrowded. Increase water circulation and biofiltration or reduce fish density.
(S30)- There is a nutrient deficiency. Check a nutrient table to see if one of these matches the symptoms. Nutrient tables can be found in good gardening books.
(S31)- There is not enough light. Move the plants to a place where they can get more light, supplement the available light, or grow more shade-tolerant plants.
(S32)- The plants are diseased. Check a plant disease book. Remove and destroy diseased plants.
(S33)- The roots are waterlogged and possible rotting. Evaluate your growing system and consult the hydroponics literature.
(S34)- The plants may be infested with detrimental insects. Confirm with an insect guidebook. Feed infested plants (insects included) to the fish. Look in a good organic gardening book for ideas about controlling future infestations.
(S35) There are no pollinators. Open the window or, if it is too cold, investigate artificial pollination techniques.
Books and Manuals
I have in my opinions on the following books, which I have found useful for understanding and learning about aquaculture, hydroponics, and agriculture in general. Usually, the most interesting materials are in magazines and journals, but there is a lot of historical, reference, and background material in larger books. Older books tend to be interesting and informative - often they contain ideas that were rejected for one or another reason by the rather narrowly focused aquaculture/hydroponic industry. Much early work on sustainable and organic methods in these fields was rejected outright or modified by the industry to conform to sterile, chemical agriculture. Now, as sustainable aquaculture and organic hydroponics arc coming into vogue, many of the best books are out of print. A good public library can be a gold mine of useful information from the past.
Chakroff, Marilyn. 1976. Fresh water fish pond culture and management. Volunteers in Technical Assistance (VITA) publication #36E
- The Peace Corps classic. Chakroff wrote this manual from firsthand experiences while serving in the Philippines with the Peace Corps. While there is little information about tanks, the information about fish, their biology, and how to take care of them is accurate and accessible. Most libraries seem to have a copy - worth the effort and expense to photocopy this 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 of his works 'include sections on aquaculture and the underlying philosophy of permaculture is both interesting and useful for anyone who likes to contemplate our place in the world. Full of new ideas and practical advice.
McLarney, William. 1998. Fresh water aquaculture. Hartley & Marks, Port Roberts, WA.
- The standard textbook on small-scale, freshwater aquaculture, McClarney was a founding member of the New Alchemy Institute and worked with John Todd 'in his early career. This book was out of print for a long time but the 1984 edition has now been reprinted and it is available through special order. Lots of information and charts, but a lot of the contact information is out of date and useless. He tries to promote using North American species for aquaculture as opposed to introduced species like carp. I would not recommend purchasing this book unless you want to raise N. American species, want more technical information about aquaculture, or are interested in other forms (such as ponds, lakes, cages, etc.)
Logsdon, G. 1978. Getting food from water. Rodale Press, Emmaus, PA
An excellent but out of print book. Seems that all the alternative agriculture organizations were running interesting programs on aquaculture and aquaponics in the seventies. Now Rodale publishes magazines like "Men's Health" and the New Alchemy Institute is defunct. This book is an excellent alternative to McClarney's text. It Is written in a more accessible style and seems to be more on the scale of home gardeners. There's even an account of an old man who raises catfish in a bathtub. Out of print but a valuable read 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 ecological engineering and the role of ecology in design. Not a very handsome book, but it does have some interesting ideas about aquaculture, cities, and the future of the planet. Generally, while the ideas coming out if the New Alchemy Institute are pretty cool, the books and other publications from the members of this group are sort of vague and disappointing. If this group wants the world to change using its ideas, then they need to write a detailed manual about building living machines. There are a lot of willing people out there who are sort of puttering in the dark trying to do good things but apparently missing key details.
DeKorne, James B. 1992. The hydroponic hot house: low-cost, high-yield greenhouse gardening. Loompanics Unlimited.
DeKorne is the last of the paranoid survivalists, but has developed some very useful systems for growing things hydroponically indoors. He is an inventor who has limited resources - the results are accessible, cheap, and easy 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 good hydroponics store will be stocked with his books, and libraries usually have a few copies. This book is the most accessible of his works, and although the ideas are fairly narrow-minded and conventional, at least it provides a solid survey of the hydroponic industry in general.
Douglas, James Sholto. 1985. Advanced guide to hydroponics (soilless culture).
Douglas, James Sholto. 1976. Hydroponics: the Bengal system.
- Douglas was one of the first writers about the 'new' science of hydroponics and he was very keen on organic and sustainable methods of production. If you can find any of his books, snap them up. Reading Douglas after reading Resh, you realize that Resh's entire scope would fit into a specialist chapter or two of Douglas' global perspective. Look for these books in the library.
Addey, William and Karen Loveland. 1998. Dynamic Aquaria. Academic Press.
A fantastic book about how aquariums and ecosystems work, written by two biologists. Full of explanations about how different environmental factors can influence fish and other organisms. Also has good ideas about how to stock an aquatic system with plants, fish, and other organisms.
Of all the magazines published currently, the Growing Edge is by far the most relevant and useful. It often has article about aquaponics and organic methods, and is an excellent source for latest hydroponic ideas. Practical Hydroponics and Greenhouses from Australia is equivalent to the Growing Edge in quality and outlook, but can be expensive because it is imported. The out of print Journal of the New Alchemist and the New Alchemy Quarterly have good articles about living machines but are rather difficult to find.
A good all-around gardening magazines is Organic Gardening. It is widely available and contains useful information about vegetables, composting, and the occasional water-gardening/hydroponic/aquaculture article. Older issues are better than recent issues, as the current editor seems more concerned about growing ornamentals than food.
Aquaculture Magazine the best source for industry news and format. Their articles are well written and researched, although keep in mind that the bottom-line is the driving force behind this magazine. Their annual Buyer's Guide is a must-have. It tells you where to get everything you could possibly need for aquaculture, especially sources of fingerlings.
All of these magazines have extremely useful back-issues. You can find these in a good library system or you can often buy them at a discount form the publisher.
P.O. Box 2329
Asheville, NC, 28802
The Growing Edge Magazine
Emmaus, PA, 18049
Practical Hydroponics and Greenhouses
P.O. Box 225
Journal of the New Alchemists, New Alchemy Quarterly - Both are out of print. Try contacting Ocean Arks International or your local public library to locate back issues.
Generally, your local extension agent will be able to provide you with information about some aspects of your proposed project. Here is one agency that has been particularly helpful.
Southern Regional Aquaculture Center
c/o Michael P. Masser
106A Swinger Hall
Auburn University, AL, 36849-5628
(334) 844-9208 (fax)
This center has put a lot of effort into promoting aquaculture. They have an excellent range of free publications, many of which are highly useful for recirculating aquaculture enthusiasts. They are one of the few places which promote crayfish, Chinese carps, tilapia, and exotic shrimps in the USDA system. They are also excellent sources of information about where to buy less common species. Ask for the following pamphlets in particular.
SRAC282 Tank culture of Tilapia
SRAC451 Recirculating aquaculture tank production systems. An overview of critical considerations.
SRAC 452 Recirculating aquaculture tank production systems. Management of recirculating systems.
SRAC 453 Recirculating aquaculture tank production Systems. Component Options
SRAC 454 Recirculating aquaculture tank production systems. Integrating fish and plant culture.
Herb, Frances Raising snails for food
Web access is becoming more widely available, and even In the developing world Internet is available at reasonable prices (approx. US$5 per hour) in Internet cafes. There are tons of resources on the Internet but beware anybody can write Just about anything in cyberspace and nobody checks their 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.
Jeff's half -whiskey-barrel page, while not quite as funny as Eric's is also full of information. He has a lot of different opinions from Eric, but the two end up with the same thing in the end. Jeff 's links are extensive.
The Living Technologies company site. This site is John Todd's consulting site. There are some interesting photos, information, and links, as well as examples of how Todd has applied living machines to industrial problems.
Access to Mississippi State University's excellent collection of aquaculture extension information.
- A major tilapia producer in Iowa, their site gives a good overview of this species.
- A large but disorganized site containing lots of information about tilapia.
- Swedish farmers who grow trout and vegetables in a recirculating system,
- Home page of the Sperraneo family who are successful aquaponic farmers in Missouri.
keywords to search with for internet information
hydroponics and aquaculture
living and machines
aquaculture and recirculating
alternative and aquaculture