Here’s a surprize: there are "cleaning stations" under the sea! Look at the image above, a cleaner wrasse is removing the parasites from its host, a fairy basslet nearly the same size. Note carefully the basslet’s position; it’s a signal to the cleaner that he’s welcome. A number of species have been identified as cleaners, like this wrasse sitting on a moray eel, or the banded cleaner shrimp on the orange sponge. There’s little risk that the moray will eat the wrasse, the relationships between host and cleaner are clear on this point. And the cleaner shrimp can continue to wave its colored arms to attract a potential “client” without worry.

During a cleaning “sitting” the host will remain about as calm as any client would at his or her barbershop/hairdresser.

So that’s why the manta rays come to visit the reef! Here we can see two images of mantas at the same "cleaning station" in the Maldives. The diver gives the scale. Once the "sitting" is over the ray will give a flap of its wings and go on… to eventually rejoin the waiting line.

The relationship between the cleaner and its host is called a "symbiosis"; that’s an association of two animals of different species, where each gets a benefit from the relationship. It’s one of many survival strategies on the reef. For the diver-photographer, its also an interesting opportunity to see subjects nearly motionless.