Backyard Aquaponics
A place to discuss aquaponics

i put like 20 tilapia in my ibc system and after a week 1 of the tilapia turn darker and only stay under the waterfall and any fish the get near the waterfall he/she attack and he/she is not the bigges fish in the tank but i see he did bite 2 fish tail off and i think they are not going to make it but is this posible that 1 small fish is killing my fish lol ??

He probably claimed the area as his nest. He wants to breed. Some tilapia are more agressive than the rest, and yes, I've had super aggressive ones kill a fish or two. Doubt he'd kill them all though. I usually make an early meal of the super aggressive ones. If, he's big enough. If not, stick him by himself for a while, like a few days. Usually chills them out for a bit.