im new at this like i said. well i recently bought a parrotfish, its not a blood parrot but one of those dyed ones and its really red(idk if that helps you). well i put in in the tank with my lutino oscar and Amphilophus Sagittae (black devil). the amph. and oscar have been there for quite some time. the parrot is slightly smaller than the oscar and hes is just beatin it up and locking jaws with both of the fish. ive never had a problem like this before. is this normal? the oscar has a couple of scrapes he hasnt had before. the parrot also just attacks and then hides behind a rock i have in the tank all day. i hear strange noises along the gravel in the night as well when all the lights and tank lights are off. should i maybe throw in some melafix to help the oscar? help would be much appreciated 
