Head to head
Common Starfish vs Crown-of-thorns Starfish
Common Starfish
VS Crown-of-thorns Starfish
The common starfish and crown-of-thorns starfish both feed by pushing their stomachs out over their prey, but they live in different oceans and eat very different things.
| Common Starfish | Crown-of-thorns Starfish | |
|---|---|---|
| Scientific name | Asterias rubens | Acanthaster planci |
| Arms | Five tapering arms | 7 to 23 arms, usually 25 to 40 cm across |
| Look | Usually orange to brown on top and paler beneath, with a rough surface of tiny spines | The whole upper surface covered in sharp spines up to 5 cm long, coated in toxins that cause immediate sharp pain |
| Diet | Mussels and other bivalves, as well as barnacles, snails, and worms | Almost entirely the living tissue of hard corals, especially fast-growing branching and plating species |
| Feeding method | Pulls a mussel's shell open slightly with its tube feet, then pushes its stomach into the gap to digest the animal inside | Humps over a coral, pushes its stomach out and spreads it over the surface, and absorbs the dissolved coral tissue in place |
| Habitat | Rocky shores, rock pools, and mussel beds, down to deep water | Coral reefs, from the shallows to about 30 m |
| Population | Widespread and abundant across much of the northeast Atlantic | Numbers can jump from a few animals per hectare to many thousands, outbreaks being a leading cause of coral decline on the Great Barrier Reef |
| Conservation status | Not Evaluated globally | Not Evaluated globally |
Common Starfish vs Crown-of-thorns Starfish: common questions
Which starfish eats coral?
The crown-of-thorns starfish, which feeds almost entirely on the living tissue of hard corals.
Which one has more arms?
The crown-of-thorns starfish, which has 7 to 23 arms, while the common starfish has five.
How do both starfish feed?
Both push their stomachs out over their prey and digest it outside the body.