Michael Pitts / Tracking shot of an Elephant ear coral (Sarcophyton trocheliophorum) growing on the side of a reef, with polyps moving in the current, Maldives, Indian Ocean.

Chris Newbert / Leather Coral (Sarcophyton trocheliophorum) and Pigmy Sweeper (Parapriacanthus ransonneti), Red Sea, Egypt

Chris Newbert / Leather Coral (Sarcophyton trocheliophorum) colony with polyps retracted, surrounded by schooling Pygmy Sweeper (Parapriacanthus ransonneti), sponges and soft coral, Red Sea

Chris Newbert / Leather Coral (Sarcophyton trocheliophorum) detail, Palau

Fred Bavendam / Leather Coral (Sarcophyton trocheliophorum) releasing egg-sperm bundles during mass spawning of corals on the Great Barrier Reef, Queensland, Australia

Francis Abbott / Leather coral with polyps exted {Sarcophyton trocheliophorum} Red Sea

David Fleetham / Leather coral (Sarcophyton trocheliophorum) colony with polyps withdrawn. The surrounding colonies polyps are extended and feeding, Philippines, Philippine Sea.