my cousin bought one that was about 4 inches and it was taking on just about everything, a 4 inch convict, big ol oscar, everything, did not back down.. pretty aggressive fish..
I think buttis aren't always a terror. I mean they can be and when they are, they devastate everything, but in my experience i've been able to keep them in a 300+ gallon outdoor pond, they've been able to live together (there's 5 of them) with some other cichlids.
that's wierd i've had one of these guys for five years and stands his own due to size but gets punked by a very pissed off african. it's cool to see a cichlid go heads with a fish three times it size. they don't hurt eachother of course. i'd say attitude varies from fish to fish. kinda like pittbulls, bad reputation, but some are the nicest dogs you've ever met.