I notice marks on the back of my 10" male aparcio ray. Thought it was the pleco in the tank and removed him a week ago. The wounds have gotten worse. Then i notice my 9" motoro ray chewing on his back in the morning and he was bleeding. Any way besides removing him from tank to cut down on aggression. I dont have a seperate tank to put him in now since i have small growouts in my other tanks.