Alex Mustard / Grooved brain coral (Diploria labyrinthiformis) at night with polyps extended to feed, Grand Cayman, Cayman Islands, British West Indies. Caribbean Sea.

Shane Gross / A Giant clam (Tridacna gigas) surrounded by Lettuce coral (Turbinaria reniformis), Kosrae, Micronesia.

Alex Mustard / Hard corals (including Acropora sp., Platygyra sp. and Pocillopora spp.) growing in shallow water and reflected in the surface. Ras Umm Sid, Sharm El Sheikh, Sinai, Egypt. Red Sea

Shane Gross / Elkhorn corals (Acropora palmata) at night silhouetted by a scientist's light during the annual coral spawn. Abaco, Bahamas.

Jurgen Freund / Bleached Staghorn corals (Acropora cervicornis), Great Barrier Reef, Australia, 2017.

Jurgen Freund / Timelapse of a Scolymia coral (Mussidae) feeding, lit with a UV light, Cairns, North Queensland, Australia.

Jordi Chias / Wave breaking over the reef, Table coral (Acropora) Safaga, Egypt, Red Sea.

Alex Mustard / RF - High magnification photo of Secretary blenny (Acanthemblemaria maria) in boulder brain coral (Colpophyllia natans). East End, Grand Cayman, Cayman Islands, British West Indies. Caribbean Sea. (Th...

Alex Mustard / Hawksbill turtle (Eretmochelys imbricata) male chomps on soft coral. Jackson Reef, Sinai, Egypt. Strait of Tiran, Red Sea.

Alex Mustard / A stand of Pillar coral (Dendrogyra cylindrus) growing on a coral reef, East End, Grand Cayman, Cayman Islands

Alex Mustard / Boulder brain coral (Colpophyllia natans) photographed with a long exposure with camera rotation. Taken with circular fisheye lens. Grand Cayman, Cayman Islands. Caribbean Sea.

Franco Banfi / Hard and soft corals and encrusting sponge on the structure of bio-rock, Karang Lestari Pemuteran project, Desa Pemuteran, Bali Island, Indonesia, Pacific Ocean

Alex Mustard / Scissortail sergeants (Abudefduf sexfasciatus) swimming over hard corals (Acropora sp.) on shallow reef at sunset, split level view. Gubal Island, Egypt. Red Sea.

Georgette Douwma / Coral line nursery with Acropora corals grown to reintroduce to the Bonaire, Netherlands Antilles, Caribbean, Atlantic Ocean.

Constantinos Petrinos / Purple short tentacle mushroom coral (Fungia sp.) close up of polyps. Lembeh Strait, North Sulawesi, Indonesia.

Alex Mustard / Shallow coral reef flat with corals (Pocillopora damicornis, Acropora humilis and Pocillopora verrucosa) in evening light. Gordon Reef, Strait of Tiran, Sinai, Egypt. Gulf of Aqaba, Red Sea.

Michael Pitts,Michael Pitts / Coral wall with Anthiinae schooling fish, Red Sea

Franco Banfi / Reef under the surface of shallow waters, at sunset, covered with hard corals, Brush Coral (Acropora hyacinthus) Robust Acropora (Acropora robusta) and other Acropora, Maldives, Indian Ocean

Franco Banfi / Reef under the surface of shallow waters, at sunset, covered with hard corals, Brush Coral (Acropora hyacinthus) Robust Acropora (Acropora robusta) and other Acropora, Maldives, Indian Ocean

Jurgen Freund,Jurgen Freund / Fluorescent corals (Trachyphyllia geoffroyi) Great Barrier Reef, Australia

Jurgen Freund / Fluorescent corals (Favia sp) Great Barrier Reef, Australia

Alex Mustard / Synchronous spawning of a mountainous star coral (Montastraea faveolata) at night. East End, Grand Cayman, Cayman Islands, British West Indies, Caribbean Sea.

Linda Pitkin / 2020VISION / Sunset cup coral / Yellow cave coral (Leptopsammia pruvoti), on sponge covered rock face, Lundy Island Marine Conservation Zone, Devon, England, UK, May

Alex Mustard / Boulder star coral (Montastraea annularis) spawning at night with released bundles of eggs and sperm floating away in the water column, East End, Grand Cayman, Cayman Islands, British West Indies, Car...

Alex Mustard / A large colony of Mountainous star coral (Montastraea faveolata) spawning at night on a coral reef, showing the synchronous release of bundles of eggs and sperm, East End, Grand Cayman, Cayman Islands...

Floris van Breugel / Staghorn corals (Acropora) on the coast of tropical island Ofu, one of the Manu'a islands, American Samoa. 2012.

Brandon Cole / A vibrant, busy coral reef with many species of hard and soft corals, a cloud of Scalefin anthias (Pseudanthias squammipinnis) fish swarming about, Fiji, tropical Pacific Ocean.

Solvin Zankl / GEOMAR / Polar shrimp (Lebbeus polaris) on live Lophelia (Lophelia pertusa) from Trondheimfjord, North Atlantic Ocean, Norway. Controlled conditions. Photo taken in cooperation with GEOMAR coldwater coral res...

Alex Mustard / 2020VISION / Devonshire cup coral (Caryophyllia smithii) photographed under deep blue light to reveal its fluorescent pigments, showing up as green in this photo. Plymouth Sound, Devon, UK, English Channel, July

Alex Mustard / Brain coral (Pseudodiploria strigosa) photographed under blue light to excite the fluorescence, Little Cayman, Cayman Islands, British West Indies, Caribbean Sea.

Alex Mustard / Secretary blenny (Acanthemblemaria maria) making a home in a deserved worm tube of a great star coral (Montastraea cavernosa), East End, Grand Cayman, Cayman Islands, British West Indies, Caribbean Se...

David Shale / Solenosmilia sp and eunicid polychaete and bamboo coral. Collected from coral sea mount near Dragon vent field on SW Indian Ridge, Indian Ocean.

Todd Mintz / Sharknose cleaner goby (Gobiosoma evelynae) pair sheltering in hard coral, Netherlands Island, Dutch Antillies, Caribbean

Jurgen Freund / Banded brittle star / Tiger stripe serpent star (Ophiolepis superba) on a hard coral, Papua New Guinea.

Jurgen Freund / Triplefin (Helcogramma sp) on a coral, Papua New Guinea.

Jurgen Freund / Bivalve mollusc lives in crevices in colonies of living hard corals. Only the the shell opening and mantle are visible, along with the minute eyes along its margin, West New Britain, Papua New Guinea.

Jurgen Freund / Hard corals showing bleaching caused by heat stress, West New Britain, Papua New Guinea, May 2010.

Jurgen Freund / Healthy coral reef in the shallows, West New Britain, Papua New Guinea.

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

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

Jurgen Freund / Blue sea star on massive Boulder coral (Gardineroseris planulata) North Sulawesi, Indonesia. This coral species is normally found from the Red Sea to Central America, and is relatively uncommon in the...

Jurgen Freund / Coral reef landscape with abundant whip corals, Blue sea stars and hard coral, North Sulawesi, Indonesia, October 2009.

Jurgen Freund / Large round Brain coral (Platygyra lamellina) on coral reef, North Sulawesi, Indonesia.

Jurgen Freund / Large round Brain coral (Platygyra lamellina) on coral reef, North Sulawesi, Indonesia.

Jurgen Freund / Coral reef with hard corals and cabbage coral, Komodo NP, Indonesia

Jurgen Freund / Diver swimming over massive boulder / Cauliflower coral (Gardineroseris planulata) Buyat Bay, Sulawesi, Indonesia.

Jurgen Freund / Massive boulder / Cauliflower coral (Gardineroseris planulata) with blue sea star, Buyat Bay, Sulawesi, Indonesia, Indo-pacific.

Jurgen Freund / Shoal of Blue chromis (Chromis viridis) amongst hard coral with Cloudy Damselfish (Dascyllus carneus) Sipadan, Malaysia.