Inaki Relanzon / Hawksbill turtle (Eretmochelys imbricata) swimming underwater, Nosy Be, North Madagascar.

Alex Mustard / Yellowtail tang (Zebrasoma xanthurum) male and female turn belly to belly during spawning to ensure fertilization. Temple, Ras Umm Sid, Sharm El Sheikh, Sinai, Egypt. Red Sea. This action is very fast...

Alex Mustard / Dugong (Dugong dugon) male and juvenile Golden trevally (Gnathanodon speciosus) swimming over Seagrass (Halophila stipulacea) meadow. Marsa Nabaa, Marsa Alam, Egypt.

Alex Mustard / Green turtle (Chelonia mydas) feeding on Seagrass (Halophila stipulacea), blowing sand out of nostrils, on sea floor. Marsa El Shouna, Marsa Alam, Egypt.

Alex Mustard / Green turtle (Chelonia mydas) resting on sea floor and two juvenile Golden trevally (Gnathanodon speciosus). Marsa El Shouna, Marsa Alam, Egypt.

Alex Mustard / Spinner dolphin (Stenella longirostris) pod socialising close to surface. Fury Shoal, Sataya Reef, Marsa Alam, Egypt.

Alex Mustard / Oceanic whitetip shark (Carcharhinus longimanus) swimming close to surface. Brothers Islands, Egypt.

Alex Mustard / Forster's hawkfish (Paracirrhites forsteri) on a coral reef. Jackson Reef, Tiran, Sinai, Egypt. Strait of Tiran, Gulf of Aqaba, Egypt.

Alex Mustard / Tiger cardinalfish (Cheilodipterus macrodon) male mouth brooding a clutch of eggs behind his sharp teeth. Gubal Island, Egypt. Strait Of Gubal, Red Sea.

Alex Mustard / Yellowtail tang (Zebrasoma xanthurum) male courting a female prior to spawning at dusk on a coral reef. Temple, Ras Umm Sid, Sharm El Sheikh, Sinai, Egypt. Red Sea.

Vincent Grafhorst / Minden / River in sandstone cave, Sof Omar Cave, Ethiopia

Vincent Grafhorst / Minden / Crater of active volcano at twilight, Erta Ale, Danakil Depression, Ethiopia