RBP arent exactly the toughest fish in the world its kinda like jeckel and Hyde with them they either kill what ever you put in with them or they get killed I have a brief experience with a 8 inch RBP...
Well I had a 90 gal with Two 12 inch Oscars, Two Red Devils one 10 inches the other maybe 6 inches well we wanted to add some thing different and a friend of ours had this 8 inch RBP in almost the same set up but he had all Oscars and his situation was working out geat but just wanted to keep the oscars, thought the RBP was kinda boring... Well anyways, we had him for about 3-6 months not sure how long but it was working out fine but my little red devil (6inches) was kinda nipping at him a little bit nothing to worry about but came home one day and my 10 inch red devil was missing his hump and was floating to the top of the water... Well we thought it was the RBP because who else would have done that to a (10inch) Red devil... Right!!! Well about a week later the RBP is all jacked up with the little Red Devil picking at him... So if that aint jeckel and hyde I dont know what is, to eat a 10 inch red devil but then get eatin buy the same type of fish but 4 inches smaller very weird if you ask me.... But thats why I dont do RBP anymore I like more then one type of fish in my tanks...