Tilapia in Aquaponics
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.
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.
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.
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.
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.
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