So for my 21 gallon I've gone With a west African theme. I know all of the fish that I want but i'm not sure if all of them can go in a tank this size. I want 1 african butterfly fish, 2 kribs (or blockhead cichlids), 6 to 8 red eye African tetras, and 4 upside down mouth catfish (Synodontis nigriventris). Yes the tank will be heavily planted.