Head to head
Common Starfish vs Brittle Star
Common Starfish
VS Brittle Star
The common starfish and brittle stars are two groups of echinoderms with five arms that live on the seabed, but they move and live in very different ways.
| Common Starfish | Brittle Star | |
|---|---|---|
| Scientific name | Asterias rubens | Ophiuroidea (a class of more than 2,000 species) |
| Relationship | A starfish, one of the echinoderms | A brittle star, another group of echinoderms |
| Arms | Five tapering arms | Five long, thin, flexible arms clearly set off from a small central disc |
| Movement | Moves and grips with hundreds of tiny tube feet along the underside of each arm | Moves by flexing its arms in a snake-like, side-to-side wriggling motion |
| Diet | Mussels and other bivalves, as well as barnacles, snails, and worms | A carnivore and scavenger eating small invertebrates, organic debris, and suspended particles |
| Arm loss | Can regrow a lost arm, which it may shed to escape a predator | Arms detach readily when it is seized, and are regrown over weeks to months |
| Habitat and range | Rocky shores, rock pools, and seabeds in the northeast Atlantic, from the shore down to deep water | Marine environments worldwide, from tide pools and coral reefs to considerable depths, sometimes in dense carpets |
| Conservation status | Not Evaluated globally | Least Concern |
Common Starfish vs Brittle Star: common questions
Why is it called a brittle star?
Its arms detach readily when it is seized or stressed, a defence called autotomy, and it regrows them over weeks to months.
How does a starfish move?
It moves with hundreds of tiny tube feet along the underside of each arm, which work by water pressure.
Are they related?
Yes, both are echinoderms, the group that also includes sea urchins and sea cucumbers.