Is there anything I can do?

[foreveringlass]

A few weeks ago I bought a Royal Gramma from my LFS. Brought him home and dripped him slowly. When I added him to the tank he was sucking air from the top, while floating upside down. I thought for sure he was a goner. I covered the tank to reduce his stress and hoped for his sake he would pull though. He did...mostly. He now swims sideways. He is always on his side! Is there a fix for this?
Thanks