Sue Daly / Barrel jellyfish (Rhizostoma octopus) swimming past, Sark, British Channel Islands, UK, September.

Alastair MacEwen / Time-lapse of toadspawn from a Common toad (Bufo bufo) developing, emerging and feeding on nutrient jelly, Somerset, England, UK, April.

Alastair MacEwen / Close up time-lapse of frogspawn from a Common frog (Rana temporaria) developing, emerging and feeding on nutrient jelly, Somerset, England, UK, April.

Luis Quinta / Moon jellyfish (Aurelia aurita) near the surface, Santa Maria Island, Azores, September.

Georgette Douwma / Upside down jellyfish (Cassiopeia andromeda) Lembeh, Sulawesi, Indonesia.

Alex Mustard / Red eye medusa (Polyorchis penicillatus) with hitchhiking amphipods (Hyperia medusarum). Browning Pass, Vancouver Island, British Columbia, Canada. North East Pacific Ocean.

Franco Banfi / Freshwater jellyfish (Craspedacusta sowerbii) Lake Lugano, Ticino, Switzerland. August. Invasive species.

Franco Banfi / Freshwater jellyfish (Craspedacusta sowerbii) Lake Lugano, Ticino, Switzerland. August. Invasive species.

Jordi Chias / Atolla jellyfish (Atolla wyvillei) with Gentoo penguin (Pygoscelis papua) in the background near the surface. Antarctic Peninsula. Finalist in the Underwater category of the Wildlife Photographer of t...

Juergen Freund / Split level of large Purple crown jellyfish (Netrostoma setouchina) in shallows of mangroves. Mali Island, Macuata Province, Fiji, South Pacific.

Barry Bland / Fried egg jelly fish (Cotylorhiza tuberculata) Mediterranean Sea.

Gabriel Rojo / Yatay palm / jelly palm (Batia yatay) trees silhouetted at sunset, El Palmar National Park, Entre Rios Province, Argentina