I have a 7 gallon tank with 2 mollys and a crab.. I got a algae eater at Wal-mart and the stupid lady that works there put my Warm water fish in with a gold fish in the cold water and put it into shock and it died as soon as I got home.. So I looked at him a while and thought dang this thing is tiny.. So i was looking it up on google and saw that you can get catfish bottom feeders... Do you think you can mix a catfish with my other fish and crab? If so.. What kind of catfish should I get?