Diving with Crown-of-thorns Starfish
Lanta Marine Life | Acanthasteridae
There are only two species in this starfish family, the Short-Spined Crown-of-Thorns Starfish (Acanthaster brevispinus) and the Common Crown-of-Thorns Starfish (Acanthaster planci), which is spotted at all dives sites around Koh Lanta.
Both species are found in the Indo-Pacific region, but we only see the Common Crown-of-Thorns Starfish at the dive sites around Koh Lanta.
These starfish are disc-shaped, multi-armed starfish, starting life with the typical 5 arms, but growing many more as it matures. They are the largest starfish in the world
Members of this family are densely covered in sharp, poisonous spines, have very flexible arms and large stomachs.
The colour is usually a varying shade of blue, purple, red, brown or grey, with variably coloured spines, sometimes with yellow tips or orange.
1 species found on this page:
Common Crown-of-Thorns Sea Star
(Acanthaster planci)
The Common Crown-of-Thorns Sea Star is a large starfish, variably coloured red to purple, yellow and tan. There are 12 - 19 arms, covered with sharp, poisonous spines which can give a very painful sting.
The diet includes coral polyps, and several individuals can consume large areas of coral within a very short period of time. This species can occasionally form very large colonies which can then devastate a coral reef.
Acanthaster planci @ Hin Bida
It is thought that one of the main causes of population explosion is excessive agricultural run-off, flooding areas with nitrates and nutrients. Dangerously large populations which threaten to destroy a coral reef can be controlled by injections of sodium bisulphate.
Common Crown-of-Thorns Sea Star @ Koh Bida
This sea star grows to 40 cm and can fully regenerate an individual adult from a severed limb. DNA analysis suggests that the Common Crown-of-Thorns Sea Star comprises 4 subspecies, each with its own distinctive range.
Diving with Crown-of-thorns Starfish around Koh Lanta
Scuba Diving & Snorkel Trips
If you'd love a chance to spot Crown-of-thorns Starfish on one of our daily high season diving trips from Koh Lanta then send us an email to info@diveandrelax.com.
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Find Out More
Indo-Pacific Marine Life Guides
- Allen, G., Steene, R., Humann, P., DeLoach, N. (2003) Reef Fish Identification, Tropical Pacific. Jacksonville, FL., USA: New World Publications, Inc., ISBN 1-878348-36-1.
- Humann, P., DeLoach, N., (2010) Reef Creature Identification, Tropical Pacific. Jacksonville, FL., USA: New World Publications Inc., ISBN 978-1-878348-44-9
- Debelius, H. (2013) Indian Ocean Reef Guide. Frankfurt, Germany: IKAN - Unterwasserarchiv, ISBN 978-3-939767-52-7.
- Debelius, H. (2004) Nudibranchs and Sea Snails, Indo-Pacific Field Guide. Frankfurt, Germany: IKAN - Unterwasserarchiv, ISBN 3-925919-51-1
- Erhardt, H., Knop, D. (2015) Corals Indo-Pacific Field Guide. Frankfurt, Germany: IKAN - Unterwasserarchiv, ISBN 3-925919-69-4.
- Veron J.E.N., Stafford-Smith M.G., Turak E. and DeVantier L.M. (2016). Corals of the World