red empress dominance

hey folks..quick question..I've got various africans in a 55 gallon, including
what I thought was a breeding trio of red empresses...turns out I actually got
2 males.
the one that wa sold as a female and to give evryone credit LOOKED like a
female has really colored up recently. He has a malformed eye on one side but
apparently can see quite well from it. Last couple of weeks he has undergone
quite a transorfmation, taking on a more "typical" male bodyform, bulking up,
and now displaying some beautiful coloration. this of course has cased the
dominant male to do the same. the question..never having have witnessed
whatever potential battle for dominance is about to ensue with this species,
just how violent should I expect it to be? would adding new females diffuse it,
or just add fuel to the fire? how large of a harem can one male keep?
TIA