Oscars have pretty weak jaws actually, plus the reproduce like no tomorrow, and grow extremely quickly.
They also are not mean fish by any means, in no comparison to a Citrenellum, or a Dovii for that matter.
The bottom line is Oscars aren't as aggressive overall. There are some out there that will rule a tank full of rowdy large fish with no problem. But they are the exception really. All the size and power in the world won't do any good if a fish doesn't have the attitude to use it. Oscars in general are territorial/semi aggressive.
Hmmm, my 3 Oscars live with some pretty aggressive Cichlids (see signature) they aren't no push over...But they aren't aggressive either, they just defend themselves.
yes my 3 oscar are scared of my clown knife he bullys them some times and they just dont do eny thing he almost as big as them and just go in the corner ???:s: