well ive got a kenyi also--he grew to be so aggressive i had to take him out of the tank and throw (not literally--though i wanted to haha) him into another tank. I have a sc. fryeri in a 90 gallon right now (in a few days hes going into my 180 that im waiting for!yeah!) and he is dominant over everyone.. he doesnt nip or tear them up, but he chases them away from his "territory"
i wish i had never gotten the kenyi- but im stuck with him.