I have a 75 gal tank with a 4inch oscar, 6inch lima shovel nose catfish, 8inch clown knifefish,a 4inch redhook silver dollar, and a 3inch golden servem. Yes I know my tank will be to crowded with all these fish full grown but I will eventualy return my clown, silver dollar and my serverm when they get to big. But anyway my problem is that my oscar is being agresive torawd all of my fish even the twice as large knifefish! (he does most of the time get along with the catfish though). I just cant find myself returning my beautiful beloved oscar (i think he is a veil tail oscar), but what should I do ??? what if I put in a more aggressive fish like a red devil would that help or would it even things out or just make another bully?? I dont know?? please help me if you can :shark: