Blue Spotted Puffer

[Erik_321]

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.

[Cliving1]

If it seems to have the symptoms of ich, then it probably does. But to verify (dont like assuming if I can help it), you could pull it out and isolate for further analysis. If by expanding you mean it becomes fan like then more needle point, that was common with puffers I have had in the past. They are pretty hardy, keep an eye on it. Did you quarantine any new arrivals? What do you mean by you acclimated for a while? Length is not always beneficial.