If your looking for a pair of fish for sized tank there are alot of options, Cryptoheros is a great genus of new worlds that offers the personality and color but without the size and temperment of the big boys. Some options good options would be honduran red points, nanoletus, cutteri, and sajicas. I have those 4 plus some others in that genus and they are some of my personal favorites of all the fish I keep in my fish room.