IME they have conspecific aggression and should best be kept singly or in pairs. When I worked in a lfs my boss would put medium sized ones in a tank all together and they constantly chased each other around lip locked and had torn fins. Multiples can work in very large tanks but I think there's better options out there
Green chromides get large and are peaceful. A lot of info says they need brackish but some say no. Bocourti are a large growing C.A. Cichlid that is supposed to be even tempered. There are others but those are the ones that come to mind.