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

Nick Garbutt / Aggregation / bloom / swarm of Moon Jellyfish (Aurelia aurita) in the clear waters of Loch Na Keal, off the Isle of Mull, north west Scotland, UK, June, Photographed through the surface.

David Shale / Hydromedusa/ Trachymedusa (Crossota sp) from approx 2700m, mid Atlantic ridge, June 2010

Michele Westmorland / Snorkeler swimming with harmless Jellyfish (Mastigias papua etpisonii), Jellyfish Lake, Rock Islands, Palau, Micronesia.

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 / Pink sea fan / Warty coral (Eunicella verrucosa) with attached eggs of a Common squid (Loligo vulgaris), eggcase of a Lesser-spotted dogfish (Scyliorhinus canicula), and Spiny starfish (Marthasterias...

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.

Floris van Breugel / Tiny thimble jellyfish (Linuche unguiculata) drift with the current in the calm turquiose waters of a lagoon in Ofu, American Samoa. The window of sky is called Snell's Window, caused by refraction of...

Graham Eaton / Compass Jellyfish, in murky water, Abersoch, Cardigan Bay, Wales, July