I had a cow fish in my reef back when I was in high school. Didn’t do any research just thought it was cool and got it. From what I remember it ate pellet food and none of my fish, including a six line and bicolor angel, bothered it. Don’t remember it nipping at corals. It lived a few months before it got wedged between a couple rocks. Died the next day. It was a fun fish, would “kiss” your finger when you put your hand on the glass.