Hi, I have a 140 gallon tank with three pairs of semi-aggressive SA/CA cichlids (Firemouths,T-bars and Blue Acaras). I also have male and female Rainbow cichlids, which are a bit of a problem because they won't spawn and they can't hold their own against other fish. I am wondering, if I could replace them with a single female Salvini cichlid. There is a 4,5 inch female Salvini in my local fish shop, which I could purchase. I am mostly worried about its compatibility with my 6 inch Firemouth male (he is aggressive but poorly skilled in fighting). I would like the Firemouth pair to remain as the dominant fish in the tank. Do you think my plan could work out?