Chris Newbert / Right-handed Hermit Crab (Paguritta sp) colony in Hump Coral (Porites sp), Solomon Islands

Chris Newbert / Hermit Crab (Paguritta gracilipes) in Hump Coral (Porites sp) 30 feet deep, Solomon Islands

Pascal Kobeh / Hard coral (Porites lutea) with Christmas-tree worms (Spirobranchus giganteus), New Caledonia, Pacific Ocean.

Alex Mustard / Hard coral reef (Porites sp.) exposed by a low spring tide in front of an island. Yillet Island, Misool, Raja Ampat, West Papua, Indonesia. Ceram Sea. Tropical West Pacific Ocean.

Georgette Douwma / Kaleidoscopic image of Partially retracted polyps of Goniopora sp. Lembeh Strait, North Sulawesi, Indonesia.

Alex Mustard / Hard coral (Porites sp.) micro-atoll. A microatoll is a circular colony of coral, dead on the top from exposure to air at low tide, but living around the edge. Their presence in coral reef fossils is...

Linda Pitkin / Stony coral (Porites sp.) with Anthias (Pseudanthias squamipinnis) Ras Ghozlani, Ras Mohammed National Park, Egypt, Red Sea.

Linda Pitkin / Stony coral (Porites sp.) with Anthias (Pseudanthias squamipinnis), and diver Ras Ghozlani, Ras Mohammed National Park, Egypt, Red Sea.

Alex Mustard / Reef octopus (Octopus cyanea) emerges from its den in a hole in a large hard coral (Porites sp.) at sunset. Sha'ab Mahmood, Sinai, Egypt. Red Sea

Alex Mustard / Hard corals (Porites sp. ) grow in shallow water around limestone rock islands. Korror, Palau, Mirconesia. Tropical west Pacific Ocean

Linda Pitkin / Flowerpot coral (Goniopora sp.) Aljui Bay, Raja Ampat, West Papua, Indonesia.

Georgette Douwma / Partially retracted polyps of Coral (Goniopora sp) Lembeh Strait, North Sulawesi, Indonesia.