Another difficulty in identifying reef fish is that some of the species can change their coloration almost "at will". The photos to the left show a juvenile hogfish, Lachnolaimus maximus. In the upper photo the fish is crossing a patch of coral sand; in the lower photo (taken about 2 minutes later) the same individual has settled down in a coral head to feed.
It appears as if the fish has changed its coloration in a way that would provide camouflage. When crossing the white sands it becomes white, which would blend in better with the background and possibly protect it from notice by predators. When it is in the coral head it becomes mottled red and white, which would blend in better with that background.