I have a 180G tank that I keep 2.1 Adult Wild Angles which fight constantly, 2 Tennis ball size Red Parrots, 1.1 Adult Pink Convicts (constantly breeding in the tank), 1 Adult Kuhli Loach ( living under the gravel somewhere, rooting out Blk Worms) 1 - 7+ inch Tricolor Shark, 2 - 5+ inch Catfish that name exscapes me at the moment, 1.0 Adult kribenses, 2 - 4 inch Tinfoil, 2 - 5 inch Iridescent sharks, all of these fish live side by side with my 2.2 RTGG that range in size from approx 9 inches to 15 inches. The smaller of the two red parrotfish always steals - 100% Wheat Bread pieces from the mouth of my two largest RTGG

and has never been attacked for doing so.
I'm not saying that my RTGG don't battle, because they do but only with each other. They are easily capable of ripping to pieces or just plain out and out killing, all other fish in the tank. I'm not saying that they wouldn't eat really smaller fish, they would because when I kept them with a Arowana they used to inhale the minnows.
Wanna know more just ask.