Juergen Freund / Orange cup coral (Tubastrea faulkneri) with polyps open, Batangas, Philippines.

Juergen Freund / Orange cup coral (Tubastrea faulkneri) detail of mouth and tentacles, Batangas, Philippines.

Wild Wonders of Europe / Zankl / Golden cup coral (Astroides calycularis) Malta, Mediteranean, May 2009

Doug Perrine / Orange cup coral feeding {Tubastraea coccinea}

Jose B. Ruiz / Golden cup coral polyps {Astroides calycularis} Mediterranean

Linda Pitkin / Orange cup coral (Tubastraea sp.), and soft corals, Triton Bay, near Kaimana, West Papua, Indonesia

Linda Pitkin / Orange cup corals (Tubastraea sp.), Triton Bay, near Kaimana, West Papua, Indonesia

David Fleetham / Orange cup coral (Tubastraea coccinea) and Gorgonian coral (Gorgonia) feeding at night, Tubbataha Reef, Philippines.

David Fleetham / Wentletrap snail (Epitonium billeeanum) eating orange cup coral (Tubastraea coccinea), Indonesia.

Franco Banfi / Orange cup coral (Tubastrea coccinea) Malpelo Island National Park, UNESCO World Heritage Site, Colombia, East Pacific Ocean

Franco Banfi / Polyp of Orange cup coral (Tubastrea coccinea) Malpelo Island National Park, UNESCO World Heritage Site, Colombia, East Pacific Ocean

Solvin Zankl / Crested cup coral (Desmophyllum dianthus) a deep-sea coral, Comau Fjord, Patagonia, Chile