Image sourcing: see credits & licences
Quick answer
The crown-of-thorns starfish (Acanthaster planci) is a venomous coral predator whose outbreaks can devastate Indo-Pacific reefs. Adults reach 80 cm and are listed Least Concern.
Top questions about the Crown-of-thorns Starfish
Crown-of-thorns Starfish facts at a glance
- Weight 3 kg
- Length 80 cm
- Top speed 3 km/h
- Lifespan 6 years
| Scientific name | Acanthaster planci |
|---|---|
| Diet | Carnivore (coral polyps) |
| Habitat | Coral reefs |
| Lifespan | 5–8 years |
| Weight | 2–5 kg |
| Top speed | up to 3 km/h |
| Conservation status | Least Concern (IUCN) |
| Kingdom | Animalia |
|---|---|
| Phylum | Echinodermata |
| Class | Asteroidea |
| Order | Valvatida |
| Family | Acanthasteridae |
| Genus | Acanthaster |
Where it lives
The crown-of-thorns starfish (Acanthaster planci) is native to Indo-Pacific coral reefs. — recorded across Oceania, Asia, Africa in this guide’s range summary.
For occurrence records, see GBIF species search and sources below.
How big is a crown-of-thorns starfish?
An adult crown-of-thorns starfish measures 80 cm long — about 46% of the height of an average adult person (1.73 m) — and weighs around 3.0 kg, about 4% of an average adult’s body weight (70 kg).
Length vs an average adult’s height (to scale)
What is a group of crown-of-thorns starfish called?
Group name (collective noun)
A group of Crown-of-thorns Starfish is called a constellation.
Baby name
A baby Crown-of-thorns Starfish is called a larva.
Explore more animal collective nouns and baby animal names .
Spiny coral predator
Up to 21 arms bear venomous thorns. A stomach can be everted to digest coral polyps externally, leaving white scars on living reef.
Coral polyp digester
A single adult can consume several square metres of coral yearly. Outbreaks of thousands per reef trigger mass bleaching-like damage.
Indo-Pacific coral reefs
From the Red Sea and East Africa to the Pacific islands and Great Barrier Reef. Larvae ride currents for weeks before settling.
Outbreaks, not extinction
IUCN lists the species Least Concern. Natural cycles and nutrient runoff drive outbreaks; divers manually remove stars and breeding disruption programs protect tourism reefs.
Explore the Crown-of-thorns Starfish
Related Invertebrates
Range & geography
Conservation status of the Crown-of-thorns Starfish
The crown-of-thorns starfish (Acanthaster planci) is listed as Least Concern on the IUCN Red List. Least Concern (LC) is the IUCN's lowest-risk category, assigned to widespread, abundant species that have been evaluated and found not to be threatened. It does not mean a species faces no pressures — only that it is not currently at risk of extinction.
The crown-of-thorns starfish (Acanthaster planci) is assessed on the IUCN Red List. Look up on the IUCN Red List .
Frequently asked questions about the Crown-of-thorns Starfish
Are crown-of-thorns starfish venomous?
Sharp spines deliver painful toxins — gloves are essential when handling them.
Why are outbreaks a problem?
Thousands of stars can eat live coral faster than reefs recover, causing long-term damage.
What causes crown-of-thorns outbreaks?
Nutrient runoff boosting plankton food for larvae and removal of natural predators may both play roles.
How do crown-of-thorns eat coral?
They extrude their stomach onto polyps and digest tissue externally.
Is the crown-of-thorns starfish endangered?
No — IUCN lists it Least Concern despite its threat to corals during outbreaks.
What is a group of crown-of-thorns starfish called?
A group of Crown-of-thorns Starfish is called a constellation.
What is a baby crown-of-thorns starfish called?
A baby Crown-of-thorns Starfish is called a larva.
Sources & references
This guide is compiled and reviewed against established zoological and conservation references. Key sources for the Crown-of-thorns Starfish:
-
IUCN Red List of Threatened Species
Conservation status (Least Concern) reflects the IUCN Red List category for Acanthaster planci.
-
iNaturalist — observations & photos
Search citizen-science observations and community IDs for Acanthaster planci. Useful for range checks and recent sightings — not a substitute for formal Red List status.
-
GBIF — occurrence data
Global Biodiversity Information Facility species search for Acanthaster planci. Explore published occurrence records used in range research.
-
Global Animal Guide editorial standards
How we research, source, review, and update every guide for accuracy.
