Black Sea Nettle Chrysaora achlyos

The Black Sea Nettle is a jellyfish native not to the Black Sea but to warm waters of the Pacific coast off California and Mexico.

The bell of the jelly is a distinctive dark red-purple to purple-black and can grow to nearly a metre across. The shorter, frilly feeding tentacles and longer, stringy stinging tentacles can extend for 5-6 metres and cause a very painful sting to humans (killing small prey and stunning predators).

They sometimes appear in large swarms. Diet is zooplankton and other jellyfish.

Like other jellyfish, they have a multiform life cycle of egg, planktonic larva, polyp, ephyra and medusa.