Well, my severum buddy is probably going to be big enough to be added to the NW tank at the end of the summer... That'll leave me with a 30g free... Would that be big enough for a pair of firemouths? I've seen sites say as big as 55 and as small as 20. Since they grow to about the size of convicts, would a pair be good in a 30g? Or is that too small?