Came home late from work tonight, and decided to turn the lights on in order to try and feed the fish. When I switched it on, noticed that my blue tang (3-year old named her Dory, of course) was lying against a rock at the bottom, gills barely moving. I heard this behavior is normal for a sleeping tang, but what scared me is that the fish was pretty white and not the brilliant blue it was in the morning. After lying still for awhile, she did swim to another rock and I *think* the color restored, but I don't know if that was wishful thinking. Does anyone else see this in their tangs? Should I move the fish into isolation? Thanks!