Best i can describe it is as he swims up over the top of the rocks and heads down the other side, he dosen't pivot to right himself in relation to the surface. I think the reason for this is his mouth is most efficient in a certain position. Or it could be he dosen't care which way is up or down. Regardless a very coo fish. Also, he has not bothered any of my corals. He did wipe out a featherduster, and i can't comment about zoanthids as i don't have any. I was kinda hoping he would eat my xenia though!!