Common brittlestar

Common Brittlestars

Common Brittlestars ©Polly White/Earth in Focus

Common brittlestar

Scientific name: Ophiothrix fragilis
This large brittlestar can be found in rockpools around much of the UK, but be gentle - its arms are very brittle and will break off if disturbed.

Species information


Diameter: up to 2cm Average Lifespan: 5-10 years

Conservation status


When to see

January to December


Brittlestars are related to starfish and have a rounded disc-like body with 5 long, thin flexible arms. They really do live up to their name and will shed parts of their arms if they are disturbed or feel threatened. So look but don't touch! Common brittlestars are found all around our coasts, in rockpools in the lower shore and offshore to depths of 85m. They live on the seabed and raise their long legs into the water current to filter feed, catching plankton and detritus. They are often found in dense aggregations where food is plentiful - with numbers of 2000 per square metre recorded. Common brittlestars some in many different colours, from dull brown to purple, red, orange and yellow. Their spiny legs are patterned with coloured bands.

How to identify

There are several species of brittlestar found in British seas, which can be difficult to tell apart. The Common brittlestar is usually a greyish-brown with paler bands on the arms, but it can be many different colours. Their fragile arms are often broken off if found in rockpools - a sign of past disturbance or predation.


Found all around our coasts, but distribution is patchy on East Coast of England and Scotland.

Did you know?

Brittlestars are often eaten by their larger relatives, the Common starfish and the Spiny starfish. They hide in cracks and crevices to avoid being eaten, but can also detect a type of chemical produced by their starfish predators and so will move away!

How people can help

When rockpooling, be careful to leave everything as you found it - replace any seaweed you move out of the way, put back any crabs or fish and ensure not to scrape anything off its rocky home. If you want to learn more about our rockpool life, Wildlife Trusts around the UK run rockpool safaris and offer Shoresearch training - teaching you to survey your local rocky shore. The data collected is then used to protect our coasts and seas through better management or through the designation of Marine Protected Areas. 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.