I just purchased a Blue Spotted Puffer from me LFS. I acclimated it for a while and when I put it in my display tank i turned the lights off. The next morning it seems fine and is swimming around. However I noticed that it expands its tail like its trying to defend itself and closes it back up. It also seems to scratch off the rocks like it has ich, but nothing seems to be on its skin. Does anyone know why it's doing this? I have a 45 gallon reef tank with two clowns and a cardinal fish.