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

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

Pascal Kobeh / Close-up of the polyps out of a coral tree (Tubastraea coccinea) at night, Baja California peninsula, Mexico. Sea of Cortez.

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

Juergen Freund / Yellow cup coral (Tubastraea faulkneri), which opens at night. Misool, Raja Ampat, West Papua, Indonesia.

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

Constantinos Petrinos / Christmas tree worm {Spirobranchus giganteus} amongst Orange cup coral {Tubastrea coccinea} Bonaire, Caribbean

Constantinos Petrinos / Orange cup coral {Tubastrea coccinea} and Tube sponge, Bonaire, Caribbean

Jeff Rotman / Orange Cup Coral (Tubastraea coccinea) portrait. Egypt, Red Sea

Constantinos Petrinos / Orange cup coral (Tube coral) polyps (Tubastraea genus) Sulawesi, Indonesia

Constantinos Petrinos / Christmas tree worm (Spirobranchus giganteus) amongst Orange cup corals (Tubastrea coccinea) Bonaire, Caribbean

Doug Perrine / Diver and Orange cup corals {Tubastrea coccinea} on Tugboat wreck at night, Curacao, Netherlands Antilles, Caribbean

Flip Nicklin / Orange Cup Coral (Tubastraea coccinea) with feeding tentacles extended at night, Cocos Island, Costa Rica

Chris Newbert / Orange Cup Coral (Tubastraea coccinea), Kona, Hawaii

Fred Bavendam / Orange-spotted Filefish (Cantherhines pullus) sleeping at night among Sponges and Orange Cup Corals (Tubastraea coccinea), Bonaire, Caribbean

Fred Bavendam / Orange-spotted Filefish (Cantherhines pullus) sleeping at night among Sponges and Orange Cup Corals (Tubastraea coccinea), Bonaire, Caribbean

Constantinos Petrinos / Orange Cup corals {Tubastrea coccinea} & Tube sponge. Bonaire, Caribbean

Solvin Zankl / Orange cup coral, polyps open {Tubastraea coccinea} Virgin Is, Caribbean

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

Jeff Rotman / Cup coral polyps {Tubastraea sp} feeding at night Red Sea

Jeff Rotman / Orange cup coral feeding at night {Dendrophyllia sp} Sipaden sea, Borneo.

Jeff Rotman / Orange cup coral feeding at night. {Dendrophyllia sp} Red Sea

David Fleetham / Orange cup coral (Tubastraea coccinea), Hawaii.

David Fleetham / Orange cup coral (Tubastrea coccinea), Hawaii.

David Fleetham / Orange cup coral (Tubastrea coccinea), Hawaii.

Georgette Douwma / Orange cup coral (Tubastrea sp.) Cebu, Malapascua, Philippines, September

Angelo Giampiccolo / Golden cup coral (Astroides calycularis) off Ponza, Bay of Naples, Italy.

David Hall / RF - Reef overhang with Sea fans (Melithaea), orange Cup corals (Dendrophylliidae), Soft corals (Dendronephthya sp.), red Encrusting sponges (Porifera), Solitary tunicates (Polycarpa sp.) and Anthias...

David Hall / Moorish idol (Zanclus cornutus) swimming past a reef covered with Coral sea fans including (Melithaea sp.) and (Pseudopterogorgia sp.), Soft corals (Dendronephthya sp), (Chironephthya sp.) and (Sclero...

David Hall / Coral reef scene with Yellow boxfish (Ostracion cubicus), orange Cup corals (Dendrophyllia sp.), Branching hard corals (Acropora sp.), Sea fans (Melithaea sp.), red Soft coral (Dendronephthya sp.), Or...

David Fleetham / Orange cup coral (Tubastraea coccinea) polyps on coral reef, Hawaii, Pacific Ocean.

Franco Banfi / Orange cup coral (Tubastraea coccinea) and Sea fans (Muricea appressa) covering rock face, Espiritu Santo Island, Baja California, Mexico, Sea of Cortez.

Franco Banfi / Star coral (Astroides calycularis) covering a rock, Capri Island, Italy, Tyrrhenian Sea.

Franco Banfi / Star coral (Astroides calycularis) covering a rock, Capri Island, Italy, Tyrrhenian Sea.

Franco Banfi / Scuba diver looking at a mass of Star coral (Astroides calycularis) covering a rock, Marine Protected area Punta Campanella, Massa Lubrense, Italy, Tyrrhenian Sea.

Claudio Contreras / Cortez damselfish (Stegastes rectifraenum), Mexican Hogfish (Bodianus diplotaenia) juvenile and Orange Cup Coral (Sea of Cortez), Mexico, August

Claudio Contreras / Gorgonian and orange cup coral (Tubastraea coccinea) inside cave, San Diego Island, Islands of the Gulf of California Protected Area, Gulf of California (Sea of Cortez), Mexico, September

Claudio Contreras / Pacific mutton hamlet (Alphestes immaculatus) and Orange Cup Coral (Tubastraea coccinea), San Diego Island, Islands of the Gulf of California Protected Area, Gulf of California

David Fleetham / Dead colony of Orange cup coral (Tubastraea coccinea), only the white calcareous skeleton remaining, possibly predated on by nudibranch (Phestilla melanobrachia), Hawaii.

Franco Banfi / Coral (Astroides calycularis) Punta Campanella Marine Protected Area, Costa Amalfitana, Italy, Tyrrhenian Sea, Mediterranean.

David Fleetham / Orange cup coral (Tubastraea coccinea) close up, Philippines.