I have a Valentini, and he has been a "model fish," with the exception of ambushing most of my hermit crabs and snails
He doesn't pick at any of my zoo's or mushrooms, but since I don't have corals, I can't provide an answer for that inquiry.
As far as him always looking puffed up, can you get a picture of him? He may be holding air... How do you feed him? Has he been out of the water at all (for example, during a transfer?)