A myriad of hard and soft corals, as well as tropical reef fish on the healthy reef near Volivoli Resort on Viti Levu, Fiji, South Pacific, Pacific

A myriad of hard and soft corals, as well as tropical reef fish on the healthy reef near Volivoli Resort on Viti Levu, Fiji, South Pacific, Pacific

A myriad of hard and soft corals at Vatu-I-Ra Conservation Park on Viti Levu, Fiji, South Pacific, Pacific

Goniopora species hard coral, on a coral reef in Gaafu Dhaalu atoll, Maldives

A mixture of Acropora species scleractinic hard corals, on a coral reef in Gaafu Dhaalu atoll, Maldives

A huge Echinogorgia species sea fan, more than two metres across, on a coral reef in Gaafu Dhaalu atoll, Maldives

Staghorn scleractinic hard corals (Acropora species), on a coral reef in Gaafu Dhaalu atoll, Maldives

A growth of Acropora species, and one Goniastrea species (centre) scleractinic hard corals, on a coral reef in Gaafu Dhaalu atoll, Maldives

A mixture of scleractinic hard corals on a coral reef in Gaafu Dhaalu atoll, Maldives

A mixture of Acropora species scleractinic hard corals, growing on a coral reef in Gaafu Dhaalu atoll, Maldives

Acropora species 'plate' corals, growing on a coral reef in Gaafu Dhaalu atoll, Maldives

Heteractis species sea anemone guarded by Clownfish (Amphiprion species) on a coral reef in Gaafu Dhaalu atoll, Maldives

A shoal of small fish swimming over Acropora species hard corals, on a coral reef in Gaafu Dhaalu atoll, Maldives

A mix of Acropora species scleractinic hard corals growing on a coral reef in Gaafu Dhaalu atoll, Maldives

A giant clam along with a myriad of hard and soft corals compete for space on the substrate of Darwin's Wall, Palau, Micronesia, Pacific

A myriad of hard and soft corals compete for space on the substrate of the snorkel site known as the Milky Way, Palau, Micronesia, Pacific

A myriad of hard and soft corals compete for space on the substrate of the snorkel site known as the Milky Way, Palau, Micronesia, Pacific

Underwater view of the reef along the circumference of the Great Blue Hole on Lighthouse Reef, UNESCO, Belize

A myriad of fish and coral underwater at Hol Chan Marine Preserve, inside the Mesoamerican Barrier Reef, Belize

Soft corals and sponges underwater on Long Caye in the Mesoamerican Barrier Reef, Belize

A myriad of hard and soft corals, as well as tropical reef fish at Vatu-I-Ra Conservation Park on Viti Levu, Fiji, South Pacific, Pacific

western king wrasse (coris auricularis), male, dark pink colour with reddish-brown band running around boby and blue-green colouration over the head, wild, day, marine protected area, diving off Rottnest Island, reef edges, sand, seagrass, Western Australia, Indian Ocean. MORE INFO: social structure where dominant male, usually the biggest in the area, will have a harem of females. When the male dies or is absent for any length of time the largest female will change sex and dominate the group.

Ascidian, Didemnum molle, oscule detail, Dauin, Negros, Philippines.

Iridescent Mantle of Giant Clam, Tridacna Squamosa, Micronesia, Palau

Mantle of Giant Clam, Tridacna Squamosa, Micronesia, Palau

Iridescent Mantle of Giant Clam, Tridacna Squamosa, Micronesia, Palau

Aerial view, Kudadoo Island resort with beaches and water bungalows, Lhaviyani Atoll, Maldives, Indian Ocean, Asia

Aerial view, Kudadoo Island resort with beaches and water bungalows, Lhaviyani Atoll, Maldives, Indian Ocean, Asia

Aerial view, Asia, Indian Ocean, Maldives, Lhaviyani Atoll, Six Senses Kanuhura Island Resort, with beaches and water bungalows, Asia

Aerial view, Kudadoo Island resort with beaches and water bungalows, Lhaviyani Atoll, Maldives, Indian Ocean, Asia

Aerial view, Kudadoo Island resort with beaches and water bungalows, Lhaviyani Atoll, Maldives, Indian Ocean, Asia

Graphic structure on underside of Red Pillow Starfish (Halithyle regularis), detail, Pacific, Great Barrier Reef, UNESCO World Heritage, Australia, Oceania

Helikopteransicht, Six Senses Kanuhura Island Resort, mit Straenden und Wasserbungalows, Lhaviyani Atoll, Malediven, Indischer Ozean

Humphead wrasse (Cheilinus undulatus), Daedalus reef dive site, Egypt, Red Sea, Africa

Aerial view, Kuredu with water bungalows and beaches, Laviyani Atoll, Maldives, Indian Ocean, Asia

Aerial view, Kuredu with water bungalows and beaches, Laviyani Atoll, Maldives, Indian Ocean, Asia

Aerial view, Kuredu with water bungalows and beaches, Laviyani Atoll, Maldives, Indian Ocean, Asia

Helicopter view, Six Senses Kanuhura Island Resort, with beaches and water bungalows, Lhaviyani Atoll, Maldives, Indian Ocean, Asia

Bullethead parrotfish (Chlorurus sordidus), Marsa Shona reef dive site, Egypt, Red Sea, Africa

The Castle rock formation, Capitol Reef National Park, Utah, USA, North America

The Castle rock formation, Capitol Reef National Park, Utah, USA, North America

The Castle rock formation, Capitol Reef National Park, Utah, USA, North America

Capitol Reef National Park, Utah, USA, North America

Aerial view of the ocean floor, Heart Reef, heart-shaped reef, Great Barrier Reef World Heritage Area, Great Barrier Reef, UNESCO World Heritage Site, Queensland, South Pacific, Australia

Two divers swimming along the remaining structure of a shipwreck.

Mantle of Giant Clam, Tridacna Squamosa, Micronesia, Palau

Mantle of Giant Clam, Tridacna Squamosa, Micronesia, Palau

Iridescent Mantle of Giant Clam, Tridacna Squamosa, Micronesia, Palau

Iridescent Mantle of Giant Clam, Tridacna Squamosa, Micronesia, Palau

Iridescent Mantle of Giant Clam, Tridacna Squamosa, Micronesia, Palau

Mantle of Giant Clam, Tridacna Squamosa, Micronesia, Palau

Mantle of Giant Clam, Tridacna Squamosa, Micronesia, Palau

Iridescent Mantle of Giant Clam, Tridacna Squamosa, Micronesia, Palau