I've had a dwarf cichlid tank. In order of dominance, GBRs, nanocarra, apisto, curviceps. Kribs are probably the most aggressive dwarf cichilds I've seen tho they mostly never try to hurt other fish, just let them know who's boss. Cons get to 6 inches so I don't really consider them dwarf. Most if not all dwarf cichlids fight but can't really hurt each other.