I have two basslets in two seperate tanks (a black cap and royal gramma), and both of them dive towards the sand and glance their face off of it. None of the other fish in either system are showing disease symptoms, and they don't have any visible dots or surface irritation. Is this a normal basslet behavior? I've always had weird fish (a firefish that schools with mated clowns, etc.) but I have never seen this. Should I be worried about any diseases, or should I chalk this one up to wierd personalities?