Top Five I have rated by attitude:
5) African Featherfin Catfish: May seem strange to see a catfish on a list of otherwise all cichlids, but this cat is fierce, come near his driftwood cave and feel the wrath.
4) Nicaragua Cichlid: Only 4.5" now and already has attitude, leaves smaller and larger fish alone, but fish in that 3.5"-5" range will be tested, just ask my GT and Chocolate. Has had epic battles with my African Featherfin.
3) Cuban Cichlid: Probably not suprising that a Cuban is on my list, but at just over 2" this fish shows no fear, and has claimed one of the biggest driftwood hideouts as his own, even against larger fish.
2) Texas Cichlid: This 2.5" tiny terror is in a growout with some cons I'm growing out, t-barbs and a pleco, loves to go bowling using the t-barbs as pins, and the cons better not eat until he's done.
1) Jack Dempsey: 8+" of shear dominance. Bow your head in his presence, unless you want to fight of course. In which case expect to lose. My only fish with a body count.