These coral polyps are from a coral colony similar to the one shown in the previous gallery image. These coral polyps are ahermatypic, meaning they must rely on capturing food with the tentacles (shown here) of the individual coral polyps. In sunlight, ahermatypic coral polyps are normally retracted (this one is extended). Sometimes the polyps are extended during daylight, but this seems to only occur in areas of shade, such as on the bottom side of a large, round coral head, or in caverns, or in deeper waters. At night the polyps are extended, using their tentacles to catch free-swimming worms, plankton and other microscopic organisms. As a diver, shining a bright dive light directly on a polyp helps the coral feed, as hundreds of tiny insect-like microorganisms attracted to the light are captured by the sticky coral tentacles. The captured prey are passed to the polyp mouth (center of photo) and absorbed as food.

Identification: Tubastrea sp.

These coral polyps make great photo subjects-- I can't resist sharing more: