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Common starfish

Asterias rubens

An orange star with five arms, creeping very slowly over the rocks on hundreds of tiny tube feet.

Size
Usually 10 to 30cm across
Look for it
All year round
Where
Low on rocky shores, among mussels, and in deeper pools

My spotter's list

Creeps after you very, very slowly. Move your pointer and see.

When to look

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Starfish

Good to know

Six things about the starfish

Feet

Hundreds of feet

Under each arm are rows of tiny tube feet with suckers on the end. The starfish moves by reaching them out and pulling.

Brain

No brain, no blood

A starfish has no brain and no blood. Sea water is pumped round its body instead.

Arms

Growing back

If a starfish loses an arm, it can slowly grow a new one.

Food

Opening a mussel

It wraps its arms round a mussel and pulls steadily until the shell opens a crack, then pushes its stomach inside to digest it.

Eyes

An eye on every arm

There's a tiny eyespot at the tip of each arm. It can't see pictures, but it can tell light from dark.

Name

Not a fish

Starfish aren't fish at all. They're related to sea urchins, and many people now call them sea stars.

The real thing

Photos of the starfish

Common starfish, photo 1
Photo: Herbythyme, CC BY-SA 4.0, Wikimedia Commons
Common starfish, photo 2
Photo: Rob Wallace, CC0, Wikimedia Commons
Common starfish, photo 3
Photo: Espen Rekdal / Espen Rekdal Photography, CC BY 4.0, Wikimedia Commons
Out and about

How to spot one

Look low on the shore at a very low tide, on and under rocks and among mussels. After storms they are sometimes washed up on the beach.

Lend a hand

How to help

Never pull one off a rock, as it tears its tube feet. If you find one stranded and still alive, gently put it back in a pool.

Keep going

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