Head to head
Blue Linckia Sea Star vs Crown-of-thorns Starfish
The blue Linckia sea star and the crown-of-thorns starfish are both large, recognizable sea stars of the Indo-Pacific, but their impact on coral reefs could hardly be more different, one a harmless grazer, the other a major cause of coral loss during population outbreaks.
| Blue Linckia Sea Star | Crown-of-thorns Starfish | |
|---|---|---|
| Scientific name | Linckia laevigata | Acanthaster planci |
| Diet | Omnivore, algae and detritus | Carnivore, living coral tissue |
| Typical arm count | Five | Seven to twenty-three |
| Size | Smaller | Usually 25 to 40 cm across, sometimes larger |
| Danger to reefs | Harmless grazer | A major cause of coral loss during outbreaks |
| Defence | Can regenerate a full body from a single arm | Venomous spines |
| Danger to humans | Harmless to touch | Venomous spines cause pain, swelling, and bleeding |
| Conservation status | Not Evaluated | Not Evaluated |
Blue Linckia Sea Star vs Crown-of-thorns Starfish: common questions
Which sea star is harmful to coral reefs, the blue Linckia or the crown-of-thorns?
The crown-of-thorns starfish, which feeds on living coral tissue and, during population outbreaks, can strip large areas of reef bare, unlike the blue Linckia sea star, which grazes harmlessly on algae and detritus.
How many arms does each of these sea stars typically have?
The blue Linckia sea star typically has five arms, the usual number for most sea stars, while the crown-of-thorns starfish is unusual in having anywhere from seven to twenty-three arms.
Which of these two sea stars is dangerous to touch?
The crown-of-thorns starfish, whose venomous spines cause immediate sharp pain, bleeding, and swelling if touched, while the blue Linckia sea star is harmless to handle.