So I am planning to get rid of my JDs as they have become rather aggressive and are starting to put on some length. They still have PLENTY of room as they are both only around 4", but I have decided to take the tank a different route with a small school of Firemouths. I have always had a love for these fish and I know they will only reach around 6", so I figure when they're about an inch long, I could possibly get 5 or 6, then start to sell them off to friends as they reach their maximum size. So my question is, how many small FMs would be desirable for a 55g tank?