Cleaning stations were common among the Cayman reefs. All kinds of fish, even turtles, would wait for a turn with the various cleaner species.

But the groupers, like this big nassau at The Meadows reef, were among the most interesting. They were patient as a stone, while the tiny gobies would dart first up and down their head and gill plates, then slowly work their way into the larger fish's mouth.

Finally, they would emerge through the gills as the grouper would flex his gill opercula wide open, exposing the oxygen-rich deep red of his own underwater breathing apparatus.

Nature has a role for everything. Pretty cool.