My first system pumped from a sump to the fish tank which gravity fed into growbeds and back to the sump. I had a lot of baby tilapia result. My new system pumps from the fish tank, through mechanical filtration and settling, then gravity feeds into the growbeds and back to the fish tank. I've had NO tilapia babies survive in the new set up. I can only surmise the fry are getting sucked through the pump and shredded. (I took the sponge inlet filters off the pump since they clogged so rapidly).Originally Posted by dsrtlzrd32
My point is, that if you employ something similar, you probably don't need to stock predators for the fry.