Well I have a 110 Gallon tank with 3 oscars all about 11 inches and a buttikafri that is about 7 inches. Well it finally happened the butti went crazy and beat the crap out of 2 of the Oscars. It was bad they are missing scales, have cuts, fins that are missing chunks. So I put the buttikafri with another oscar that is way to aggro in a 55 with a divider and they are trying to get at each other threw the divider. this is going to get interesting if the divider falls. Im just glad this didnt happen when i was away for a few days cause i would have come back to a couple of dead oscars.