^Dan's idea is probably the best one. If you don't want a breeding pair, you could try adding an adult cichlid of larger size (8-10ish inches) like a jack Dempsey. Adding cichlids to a tank where another one has established territory already is always a crapshoot. If you go that route, I would take the salvini and put in in a bucket, completely re-arrange the tank, then put the JD in first, then the salvini after, and no lights for the first day. Keep a divider on hand and watch them, if it's going sour divide them. Best of luck.