I would love a 55, but I don't have the room. I know I can fit a 30 and I think I can cram a 40 gallon, but definitely not a 55. When I get my 40, how many fish should I buy? I have 3 yellow labs, a kenyi, an auratus, a clown pleco, and a juvenile common pleco (I'm aware he'll get huge, but I...