Lion's mane jellyfish

Lion's mane jellyfish

Lion's mane jellyfish ©Alex Mustard/2020VISION

Lion's mane jellyfish

Scientific name: Cyanea capillata
The long mane of tentacles that stream out from the lion's mane jellyfish is stunning… literally! Look but don't touch when it comes to these jellyfish - they give a powerful sting.

Species information


Bell: Up to 50cm across

Conservation status


When to see

May to October


It's easy to see where the lion's mane jellyfish gets its name from: the long flowing tentacles that surround the bell have all the beauty and bite of a lion. Up to 3m in length, these tentacles are packed with stinging cells and are used to catch their favourite prey: fish and other smaller jellyfish. Lion's mane jellyfish give a very nasty sting, so consult a doctor if swelling or weals are severe. In the meantime, scrape the area with a clean stick or remove the tentacle with tweezers if you have them to hand, then rinse the area with warm to hot water to reduce swelling.

How to identify

A translucent brown to reddish jellyfish with a thick mane of hundreds of long hair-like tentacles; the oldest of which are coloured dark red. They have thick, frilled oral arms under the bell, most often brownish in colour.


Found off all UK coasts in summer months.

Did you know?

Fragments of the lion's mane jellyfish's tentacles will sting you even if they're no longer attached to the jellyfish! They will still sting long after they've been on the shore.

How people can help

Report your lion's mane jellyfish sightings to your local Wildlife Trust. The Wildlife Trusts are working with sea users, scientists, politicians and local people towards a vision of 'Living Seas', where marine wildlife thrives. Do your bit for our Living Seas by supporting your local Wildlife Trust or checking out our Action Pages.