I was wondering if any of you would like to help me out in my fish tank it is a 55 Gallon. The fish I have in the tank are Two Oscars 4.5 inchs and a Blue Channel Catfish that is 1 foot or 12 inchs. Yes I know my fish Catfish is to BIG for my tank you say. but he is a lazy Person sits there but at night he is just like zoom zoom ZOOM I was just wondering what type of fish iI could put in the tank because4 the pet guy at the store tells me you can't put any other fish in the tank but im confuzzled by the people at petco and petsmart and other store so tell me what should I put in the tank.