Juergen Freund / Bean shaped polyps of an Anchor coral (Euphyllia ancora), a large polyp stony (LPS) coral. Misool, Raja Ampat, West Papua, Indonesia.

Georgette Douwma / Hard coral polyps {Euphyllia ancora} Bunaken, Sulawesi, Indonesia

Georgette Douwma / Kaleidoscopic image of (Euphyllia ancora) polyps brown and green. Lembeh Strait, North Sulawesi, Indonesia.

Gary Bell/ Oceanwide / Hard Tube Coco Worm (Protula magnifica) filter feeding in Euphyllia Coral (Euphyllia ancora), Great Barrier Reef, Australia

Georgette Douwma / Cheek-bar cardinalfish (Apogon sealei) swimming over Euphyllia ancora coral. Lembeh Strait, North Sulawesi, Indonesia.

Georgette Douwma / Coral (Euphyllia ancora) polyps brown and green. Lembeh Strait, North Sulawesi, Indonesia.

Georgette Douwma / Tentacles of Coral (Euphyllia ancora) Lembeh, Sulawesi, Indonesia. Vulnerable species.

Claudio Contreras / Batasan Island, Danajon Bank, Central Visayas, Philippines, April

Norbert Wu / Euphyllia Coral (Euphyllia ancora) with polyps extended, Ambon, Indonesia

Georgette Douwma / Hard Coral (Euphyllia ancora) polyps. Rinca, Komodo National Park, Indonesia, October.

Georgette Douwma / Hard Coral (Euphyllia ancora) polyps. Rinca, Komodo National Park, Indonesia, October.

GEORGETTE DOUWMA / Hard coral (Euphyllia ancora) polyps. Bunaken, Sulawesi, Indonesia.

Constantinos Petrinos / Tube worm (Sabellidae) on hard coral (Euphyllia ancora) Sulawesi

Doug Perrine / Acoel flatworm {Waminoa sp} commensal on tentacles of Hard coral {Euphyllia glabrescens} Gato Island, Cebu, Philippines

Juergen Freund / Colonial hard coral {Euphyllia ancora} Papua New Guinea

Birgitte Wilms / Hard Coral (Euphyllia paraencora) polyps, 60 feet deep, Solomon Islands

Norbert Wu / Euphyllia Coral (Euphyllia ancora) a type of stony coral with distinctive polyps, Papua New Guinea

Juergen Freund / Coral {Euphyllia ancora} Pacific, Philippines

Juergen Freund / Tentacles of coral (Euphyllia glabrescens) Indo-Pacific

Gary Bell/ Oceanwide / Euphyllia Coral (Euphyllia ancora) polyps, Great Barrier Reef, Australia

David Fleetham / Commensal shrimp (Thor amboinensis) on hard coral polyps (Euphyllia ancora), Mabul Island, Malaysia.

Roberto Rinaldi / Bubble coral (Euphyllia sp), Farasan Islands, Saudi Arabia.

Chris Newbert / Euphyllia Coral (Euphyllia ancora) close-up of polyps, Coral Sea

Joel Sartore / Photo Ark / Torch coral (Euphyllia glabrescens) portrait, Omaha's Henry Doorly Zoo and Aquarium. Captive.

Joel Sartore / Photo Ark / Branching frogspawn coral (Euphyllia paradivisa) portrait, Butterfly Pavilion, Colorado. Captive.

Linda Pitkin / Banggai Cardinalfish (Pterapogon kauderni), a shoal sheltering against Anchor Coral (Euphyllia ancora). Lembeh Strait, North Sulawesi, Indonesia.

Linda Pitkin / Banggai Cardinalfish (Pterapogon kauderni), sheltering against Anchor Coral (Euphyllia ancora) Lembeh Strait, North Sulawesi, Indonesia.