Tilapia Dec 29 2008
I only really recommend tilapia in Aquaponics situations where heating and climate control are a given, like indoors or a heated greenhouse or tropical climate. For tilapia to grow well, the water needs to stay above 70 F. Just to keep them alive, one needs to plan on keeping the water above 55 F.
New Babies
In Central Florida one might think that keeping the Aquaponics water warm would be pretty easy since water is a great heat sink and all. However, flood and drain gravel beds make really effective heat exchangers and tend to bring the water closer to the air temperature faster than a tank just sitting here. Even in a greenhouse, my flood and drain Aquaponics systems required supplemental heat to keep tilapia alive over winter.
Larger babies
Aside from the temperature issues for Tilapia, there are some other things about tilapia which should be well understood before choosing them for Aquaponics. They have the benefit of being easy to breed and they have the drawback of needing to control their breeding.
Babies May 30 2009
Tilapia are mount brooders, that is the female will lay eggs, the male will fertilize them and then the female pics them up in her mouth to brood them. While the female is holding eggs and fry in her mouth, she isn’t eating or growing and the more time and energy the males spend on breeding, the less energy is going into growing. If you have mixed gender tilapia in a tank and they have access to the bottom or any horizontal surface, they will be trying to breed. Being able to breed one’s own stock is an attractive side of tilapia but uncontrolled breeding in the tank will leave one with lots of small fish and few worth eating.
2 lb tilapia
To control breeding, some people will get all male fish but this is usually done with hormone laced feed for the fry or special hybrid crosses that produce all male offspring. This is rarely available to a small scale home Aquaponics producer. The easiest way to control tilapia breeding on a small home scale is with cage culture. I suspend a cage in the tank so that the fish don’t have access to the bottom of the tank.
Tilapia for dinner after over a year
question how many Tilapia or catfish could be raised in a 1200 gal tank and how many in a 3500 gal tank
That really depends on many factors.
1-How much filtration is available for that tank?
2-How much water circulation?
3-How much aeration or dissolved oxygen (and this is temperature and BOD dependent)?
4-How big are the fish going to be grown out to?
5-How willing are you to risk killing all the fish if the slightest thing goes wrong?
Personally I like to have at least 5 gallons or more of fish tank for each fish that I will raise to be 1 lb max (like tilapia tough I don’t grow them anymore.)
For the Catfish I grow, I have 10 gallons of fish tank (constant height in fish tank) per fish and 20 gallons of media bed filtration per fish with a tank turn over rate of AT LEAST 2 x per hour preferably more and 1 CFM of aeration per 400 gallons of fish tank.