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 / Bleached coral {Acropora sp} caused by loss of algae with living purple polyps. Maldives.

Peter Scoones / Bleached {Acropora sp} coral caused by loss of algae due to temperature change. Maldives.

Chris Newbert / Stony Coral (Acropora sp) and baitfish, Solomon Islands

Fred Bavendam / Stony Coral (Acropora sp) colony releasing egg-sperm bundles during the mass coral spawning each March at Ningaloo Reef, Western Australia

Fred Bavendam / Staghorn Coral (Acropora cervicornis) colony releasing egg-sperm bundles during the mass coral spawning each March at Ningaloo Reef, Western Australia

Fred Bavendam / Stony Coral (Acropora sp) colony releasing egg-sperm bundles during the annual mass coral spawning on the Great Barrier Reef, Queensland, Australia

Fred Bavendam / Staghorn Coral (Acropora cervicornis) colony with an extensive bleached area at its center, Kimbe Bay, Papua New Guinea

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

Alex Mustard / Colourful coral reef scene with Scalefin anthias (Pseudanthias squamipinnis), soft corals (Dendronepthya sp.) and hard corals (Acropora sp.). Ras Mohammed National Park, Sinai, Egypt. Red Sea

Alex Mustard / Lemon coral goby (Gobiodon citrinus) shelters in the branches of a coral (Acropora sp.). Gubal Island, Egypt. Strait Of Gubal, Red Sea.