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.

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

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

Graham Eaton / Common / Moon Jellyfish (Aurelia aurita) seen from below. Cardigan Bay, Wales, June. Highly commended, marine category, British Wildlife Photography Awards (BWPA) competition 2012.

Pete Oxford / Upside down Jellyfish (Cassiopeia sp) Jardines de la Reina National Park, Cuba, Caribbean

Alex Mustard / 2020VISION / Compass jellyfish (Chrysaora hysoscella) swimming over a rocky reef, Plymouth, Devon, UK, August. Did you know? Compass jellyfish change gender throughout their lives, starting off male, and later bec...

Doug Perrine / Swarm / aggregation of venomous Moon jellyfish (Aurelia aurita) Port Fidalgo, Prince William Sound, USA, July

Suzi Eszterhas / Two Purple / Striped Jellyfish (Pelegia / Chrysaora colorata) Monterey Bay Aquarium, California, USA, Captive

Alex Hyde / Swarm of Common / Moon Jellyfish (Aurelia aurita)in sea loch, Isle of Mull, Scotland. June. Digitally stitched panorama.

Alex Hyde / Swarm of Common / Moon Jellyfish (Aurelia aurita)in sea loch, Isle of Mull, Scotland. June.

Alex Hyde / Common / Moon Jellyfish (Aurelia aurita) close-up, breaking the water's surface, Isle of Mull, Scotland. June.