Integrated Aquaculture Using Tilapia and Plants
Carol - to recap our understanding of the "talopia systems" inquiry first
addressed, you have a local high school beginning a tilapia project, and
wanted specific information on raising tilapia in tanks with rabbits or
chickens suspended in cages over, with the waste feed and feces dropping
down to feed the fish.
You received a reply from Richard Fowler which stated that this practice is
indeed being utilized in poultry-over-fish farming in South Africa.
I replied "Although we do not use animals over ponds in our system, we do
use an integrated approach, and one that is easily adaptable to school
projects. All is indoors, fish are raised in tanks, and plants grown in
beds filled with gravel. All are constructed of easy to find materials, and
if the school has a greenhouse available, much of the basic expense is cut out.
Please check our web pages at www.townsqr.con/snsaqua, review our system,
and if you think it will work for this site, let us know if we can help
further with this project."
and further wrote that "You may want to add the following web site to your
list of resources. It's for the American Tilapia Association and maintained
at the University of Arizona.
They have a wealth of informtion and wonderful links, as well as pictures
and explanations of their own integrated systems. Well worth the time to
You responded with the following:
>Thanks for the tilapia web address and I will take a look at the site.
>Meanwhile, I am hoping you may be able to help me with the issues that the
>gentleman below raises regarding integrated tilapia and livestock systems.
>I know nothing about the systems myself, but thought these systems worked
>well and were proven. I would very much like to respond to his comments
>but do not have the information to do so. Can you help or forward this
>message on to someone who can? I need to get the story straight before I
>set the highschool kids onto this project.
>Please either respond directly to the gentleman (james, I think, from his
>address) and cc me, or respond to me and I will get back to him. Your
>assistance would be greatly appreciated.
>>From: Ingrid Tenggren <email@example.com>
>>Date: Sun, 26 Jan 1997 11:58:58 -0800 (PST)
>>Subject: talopia project
>>Hi, Carol. I emailed a copy of your posting (to the sus.agr group) to my
>>husband, James. He's got almost 20 years experience raising fish and
>>animals; we live on a small farm in Redmond, east of seattle. He was concerned
>>about some assumptions made in the email posting, and sent me the following
>>reply. If you want to ask any more questions, his email address is:
>>This is a very, very disturbing letter because it is so mis-informed. In a
>>closed system, dumping a lot of fecal matter into a fish pond will
>>quickly foul the water and kill the fish. This is especially true of
>>rabbit and chicken droppings, which are very "hot" fertilizer--they have
>>lots of nitrogen, which is part of the harmful ammonia cycle in a closed
>>water system. Further, although Tilapia are very adaptable omnivors,
>>chicken and rabbit feed is not designed for fish, and so the fish will
>>not do as well.
>>Although this post doesn't come out and say it, many, many people
>>somehow think fish can eat feces. They do NOT eat the feces of other
>>animals. Also, just getting the little bits of feed that slip through
>>will not be enough for Tilapia, or any fish intended for use as a food
>>fish. Tilapia will begin to breed at a size as small as 2 to 3 inches in
>>length, and not grow much more if kept on short rations. They need to be
>>fed adequately or all you're doing is keeping pets. They'll never reach
>>a useful harvesting size.
>>Even scarier is if someone tries this in an open system, like an outdoor
>>pond, and it really gets bad if there is any kind of stream or overflow
>>flowing out of the pond. In such a case, you're dumping nasty waste
>>products directly into the environment. Chickens are loaded with
>>salmonella and other nasty things that cause people to get very sick.
>>I would assume that the source of this is that in some places, the ponds
>>(for whatever reason) are not particularly fertile, and can't support
>>fish. In SOME cases (particularly 3rd-world countries), adding a LIMITED
>>amount of nitrogen-based fertilizer will help START or accelerate a food
>>cycle, which is that the plant life will grow faster, and thus the
>>animals in the food chain will have more to eat and thus grow larger,
>>etc. However, the animal life will also be producing waste material, so
>>if waste-dumping is continued without a significant percentage of the
>>water changing regularly (meaning both inflow and outflow to reduce
>>wastes), the water will turn into a foul-smelling death-trap.
>>Another note about Tilapia is that they are extraordinarily prolific, and
>>unless harvested will quickly tax the capacity of whatever body of water
>>So--if you want to keep fish, great! If you want to keep chickens or
>>rabbits, great! But don't dump ANY land animal's feces into water unless
>>that water is on it's way directly to plants, and the plants are not
>>somewhere where there is easy runoff into moving or still water.
Carol - In response to this message from James, I find much in his letter
that I can agree with. I do believe, however, the practice of feeding
tilapia on animal waste products is being done even here in the U.S. I
understand the water quality is very poor, and there is some discussion
about off-flavor fish, although we've also been told that in a blind taste
test years ago, the tilapia that had been primarily fed on hog manure had
the best flavor of all. With all the problems in the UK, you would think
this an unhealthy practice.
Primarily, the tilapia do not consume the waste, but feed on the algae that
is produced through its breakdown process. They are algae eaters and are
quite efficient at that. I agree with James that this process should leave
the fish nutritionally deficient at the least. However, not having
experience with this type of system, I don't feel qualified to make any kind
of judgement of those who have and are using it.
For my share toward your original information search, I can only provide you
some background of our type of closed system to see if it fits with the
cirriculum choice of your high school students.
What we've attempted to do with our system is to "take advantage" of the
synergystic relationship between fish and plants. We attempt to balance x
quantity of fish biomass with x quantity of growing plants, gravel and
bacteria to create as close as possible a "simulated natural" environment
for each to effectively grow. We do this in a greenhouse, with the fish in
800-1000 gallon tanks. They are fed a high protein commercial feed so that
their nutrition level is correct. The fish waste and any excess feed is
pumped with the water from the bottom of the tanks directly into growing
beds through PVC piping into growing beds.
Plants are grown in gravel - gravel for the bacterial surface it offers, and
also for plant support. They use for their growth that which would foul the
water for the fish. Each tank has a designated group of growing beds. When
the water has flowed through the beds, it is returned to a sump bucket, and
returned to the fish tank, aerating at the same time by water being forced
through a PVC end cap with many holes.
The fish water quality stays high, plant growth is higher than under outside
conditions, and each portion of the system maintains the other. Further
description of this system can be reviewed on our web page
If you would like more information, please let me know. We are always
interested in stimulating our young people's minds by having them consider
new and different methods. It promotes diversity in people, as well as the
paths their lives will take, and we believe they are more receptive to new
ideas than some of us who are older.
Hope your search is successful.
S&S Aqua Farm
West Plains, MO