Well I got 4 Cory cats of one species(forget which, they have spots and the name began with M) but I have lost two of them, so two left. Now upstairs in my ten gallon I had only one fish left, my Bronze cory. I did not want to move him since I was afraid the change would kill him, I've had him for 4 years. I decided to go ahead with it and he is enjoying himself in the 55 gallon downstairs. He wants to school with the other cories since he is desperate and has not schooled in 4 years but they have no interest since he is not their species. So I need more cories of both species. I was wondering how many of each i should get, I want them to be happy but I don't want my tank to be completely taken over by them (if I had my way I would want a ton but my dad does not like bottom feeders) so how many more should I get of each?