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 / Bubble coral shrimp (Vir philippinensis) on Bubble coral (Plerogyra sp). Anilao, Philippines.

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

Gary Bell/ Oceanwide / Golden Damselfish (Amblyglyphidodon aureus) juvenile among coral, Great Barrier Reef, Australia

Duncan Murrell / Coral formations at low tide in Prony Bay in the Southern Lagoon, Lagoons of New Caledonia: Reef Diversity and Associated Ecosystems UNESCO World Heritage Site. New Caledonia.

David Fleetham / Whitetip reef shark (Triaenodon obesus) resting on sea floor. Kauai, Hawaii.

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

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

David Fleetham / Cleaner wrasse (Labroides dimidiatus) swimming alongside Golden damsel (Amblyglyphidodon aureus) looking for parasites, Fiji, Pacific Ocean.

David Fleetham / Fire Dartfish / Fire Goby (Nemateleotris magnifica) against colourful coral. Fiji's outer reef.

David Fleetham / Bubble coral shrimp (Vir philippinensis) on Bubble coral (Plerogyra sp), Philippines.

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