I have a bicolour foxface rabbit fish that eats all the small ones in my tank, but he leaves the few that were already of a decent size when I put him in. I have a couple that look really cool, about 2 inches in diameter and covered in a bright pink corraline. I used to carefully manually remove them, but dont bother now as the foxface keeps them in check. I had one that I plucked off the rocks, I was squeezing it to see how tough the skin was, when it burst, and sprayed salt water right in my eye lol. At least my wife thought it was funny!