The ocean is a fascinating place filled with all kinds of unique behaviors. One, in particular, is that of the cleaner shrimp, in this case the scarlet lady shrimp, and numerous fish who constantly visit it's little nook on the reef in order to be rid of parasites. Because the shrimp provides a service to the larger fish, it is afforded a kind of 'diplomatic immunity' -- the fish will not eat its cleaning host and allow it to enter its mouth and gill area. This behavior is known as symbiosis.
The wonder of this behavior is that the shrimp is not picky on who it cleans, which in this case was Laz. Good thing he had a peanut butter and jelly sandwich before the dive!