I would expect from my experience that the cichlid will start to get shredded fins on a night time. Even at 4” the cichlid is not large enough to be ignored. IMO needs to be double this size and still growing larger. The only thing I seem to be able to house with them is more of the same. Yes they argue and have their own quarter of the 4ft tank but they don’t eat each other. When in the community they were even eating young gibbiceps plec. Anything they came across at night.