I have 2 oscars an albino and a tiger both 11"+
Albino = the most gentle giant ever, even a male gt I had sometime back did not bother him, same with my 9" texas. He did eat a semi decent sized firemouth I was stupid enough to try with them though.
Tiger oscar was nice until he got to about 8-9", he (or she I dont know) and my male gt fell out so bad I had to rehome the gt as it shreded him in the space of a few hours, he now bullys the texas about but wont leave the albino's side and never fights with it (pair forming perhaps?)
School bully type fish imo.