He's never killed a fish in his tank actually. There used to be 3 bluegills with him then the 2 bigger ones killed the little guy then one bluegill picked on the other one a lot and was killed by my 8" bullhead in a different tank. But I have seen the big guy get ahold of the bluegill and shake him a bit but he's too big to eat whole luckily. He's a gentle giant, for the most part haha