i have never had Jack Dempseys before but i got 2 them for free from a guy on craigs list. they are in a 75gal tank. they were in a 40gal. the male is about 6 in and female is about 4in. she is really beat up. at first they got along good in my tank then at night after the lights go out i would hear splashing and my thinking was that he is attacking her again, like he did in the last owners tank. i guess my question would be how can i stop this as i would like them to spawn and get some babies. should i add other fish? i know Jack Dempseys are very aggressive so what could i add? does a fishes diet affect their aggression? like if i feed them more meaty foods with they be more aggressive? Any advice for a new Jack Dempseys owner would be helpful. i have had another 75gal with African Cichlids for years so I'm not new to fish at all just Jack Dempseys.