+66 (0)89 050 3009

Diving with Crown-of-thorns Starfish

Koh Lanta Marine Life | Acanthasteridae
Snake Sea StarsToxopneustidae Sea Urchins

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.

Common Crown-of-Thorns Sea Star (Acanthaster planci)

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 (Acanthaster planci)

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.

Koh Lanta Diving with Crown-of-thorns Starfish

If you'd love a chance to spot Crown-of-thorns Starfish on one of our daily Koh Lanta diving trips then send us an email to info@diveandrelax.com.

Join our high season speedboat dive trips to some of Thailand's best dive sites and enjoy small groups, short journey times, and a focus on great personal service, safety and fun.

Book online to save 10% on dive trips and scuba courses on Koh Lanta.

Find Out More

More Marine Life References and Further Information


Dive Trips & Scuba Courses

Send us an email and we'll get back to you as soon as possible.

  • Please let us know:

    • when will you arrive on Koh Lanta?
    • your previous dive experience?
    • which diving activities you are interesed in?
  • If you're already here on Lanta, you can call or WhatsApp +66 (0)89 050 3009