How big will they get? will you keep them in a 60 gal. tank? sounds interesting.

-Sheila

If you want to max out their weight, I'm assuming they could get to 3-4 lbs. But, about 35% of their body weight is in fillet meat, so if you want two six ounce fillets per fish, that comes to about 2 lbs. live weight at harvest.

My plan is to raise them through the winter so they're a few ounces in live weight. Then, about May I'll put them outside in large tanks and really throw the food to them. They also eat by gill-straining algae, so if algae is available in the water they actually gain much more weight than just feeding would support.

I'll harvest them throughout the summer and into the fall. Under normal intensive aquaculture conditions, you can keep about 1/4 lb. of tilapia per gallon of water. So, a 400 gal. tank could support 100 lbs. of fish at any one time. To answer your specific question, if you had a really good filter system, air pump, and heater on a 60 gal. tank you could raise about 15 lbs. of tilapia in that tank all the way up to adult (harvest) size.

Here's the remarkable bonus. I have the fish in two greenhouses. One is slightly shaded and grows mostly orchids. The other is clear and grows vegetables in the winter. If you drain a little water out of each tank every day and put it on the plants you will not believe the results. My orchids have never looked better; deep green leaves and growing and flowering like mad. This warm aquarium water with a trace of nitrogen seems like the perfect fertilizer.

Great idea! love the use of the water on your plants.

Well, I've actually kind of taken the whole Circle of Life thing to a nutty --but to me, entertaining-- extreme. Here's how it's supposed to work: I take my kitchen waste and compost it in a tumbling composter. I also throw in about 50/50 green and brown waste material; mostly lawn clippings or garden cuttings and chipped wood. I make the compost and put it in a giant worm bin marketed under the snazzy name of the Worm Wigwam. The worms double in number about every two months and can consume in this bin up to 20 lbs. A DAY of kitchen scraps. Then, I take the worms and feed them to the tilapia along with some pond weed, commercial fish food, etc. Then, I take the wastes in the tilapia water and grow food like lettuce in hydroponic troughs. Lettuce and basil seem to thrive on fish waste; tomatoes may need a little more nutrients than you get in fish water. Then, I eat the lettuce and what's left over becomes kitchen waste. I take the kitchen waste and compost in a tumbling composter....

Sounds too much like a free lunch? Well, it does require that I add energy inputs to keep the system going; mostly in the form of commercial fish food. (This is fairly cheap. A 50 lb. bag costs about $33 and will last you many months.) But, you have to remember that the major energy input that keeps the system working is free: the sun. The sun grows the vegetable matter that is composted and grows the hydroponic vegetables. I also have three solar water heating panels on the roofs of two sheds next to my greenhouses. These provide the warm water for the tilapia. In fact, they're so effective that you have to regulate them with a thermostat or they'll overheat the water, even on cold days in the winter.

So, like I said, kind of nutty, but entertaining. I've been doing some experiments with components of the system for a couple of years, but this will be the first winter where I try and tie it all together. So far so good. We'll see.

i am soooo interested in raising tilapia and am waiting to get more info. would love to know others that raise them. i live in california.

diana

Years ago in "organic Gardening"magazine they showed a big stock tank in a greenhouse and raised tilapia and heated the greenhouse too.I always thought it was a neat idea.Toured a local place that shows all the green stuff and they had a dome greenhouse with a big fish tank in one side.Cool!Posy Pet

Sounds like you have a great system! Thanks for the detailed info on talapia. I had looked into it at one time, when I had a pond and aquariums (once upon a time), as many people are raising talapia in tanks in their basements now. It's more trouble than I have time for at the moment, so I'm not going to go there, but I'm glad to see that others are. It may be something I will do in the future so I will save all of this info.

You will have to "season" the outdoor containers as well, before you put all the fish in, but you can speed that up by seeding the outdoor filter with bacteria saturated material from your indoor tank and adding a little ammonia (or a couple of fish) - takes about a week or so.