I know my setup is quite weak right now for my red bellies, but I didn't expect them to grow as fast as they did. I have a 10 gallon tank with 2 3 inchers in it. I feed them beefheart and bloodworms, and I guess that is why they bulked up so fast. I want to get a 55 gallon but don't have the funds right now, and I wanted to know when it would become vital that I would have to upgrade or it would hurt the fish??? ???