Sea animals have their gills and other body parts cleaned by other animals, such as cleaner shrimp or wrasses (small fish). Often they travel to places where the cleaning critters hangout - this we call a cleaning station. This image was taken at a cleaning station.
Yap, Micronesia is known for two such places for Mantas. We waited quietly for a few minutes then silently a 10 to 12 foot manta arrived, was cleaned for a couple of minutes, then went on its way. With good luck another manta would arrive; then another. What a thrill it was to be so close to these huge, but gentle creatures. Their mouths are large and with the help of the paddle like cephalic lobes the mantas scoop up volumes of water rich in planktonic crustaceans and very small fish.
This image is available to 7 x 10.