A 40 breeder might or might work out...
In all honesty every pair is a bit different, they are like married old couples... some get a long great some kill each other :lol:
Personally I would ask the seller how aggressive the male gets.
If you do try this... get alot of rock!
Just because it only gets 3 inches... doesn't mean a thing with these guys. They can and will kill in a 6 foot tank if they don't like someone.