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.

Alex Mustard / Split level view of shallow coral reef in the Red Sea at sunset. Gordon Reef, Sinai, Egypt. Strait of Tiran, Gulf of Aqaba, Red Sea.

David Fleetham / Reef scene with Mexican / Streamer Hogfish (Bodianus diplotaenia) in adult male phase and schooling Cardinalfish (Apogon pacifici). Gordon Rocks, Galapagos Archipelago, Ecuador.

David Fleetham / Reef scene with Mexican / Streamer Hogfish (Bodianus diplotaenia) in adult male phase and schooling Cardinalfish (Apogon pacifici). Gordon Rocks, Galapagos Archipelago, Ecuador.

Linda Pitkin / Bigeye fish (Priacanthus hamrur) night time colour Gordon Reef, Straits of Tiran, Egypt, Red Sea.

Linda Pitkin / Side-gilled slug, Pleurobranch (Pleurobranchus grandis), at night Gordon Reef, Straits of Tiran, Egypt, Red Sea

Lucas Bustamante / Bumphead parrotfish (Bolbometopon muricatum) and King angelfish (Holacanthus passer) swimming over reef, Gordon Rocks, Galapagos National Park, Pacific Ocean.

Noemie Stroh / Gorgonian fans (Annella mollis) on a healthy reef, Gordon Reef, Strait of Tiran, Red Sea, Egypt, September.