Someone takes a bite, you’re gonna notice. It doesn’t seem to hurt. But when I can’t tell one fish from another, it helps to have a piece missing. These fish usually are paired. In this situation they were grouped happily swimming near the edge of the reef. I have been here again and did not see this one special bitten fish again. Maybe the ogre came back and finished the job. I can’t imagine the fin is a good snack. But hey, I’m not a fish eater in general.