Lion’s mane jellyfish in Thailand

A tropical relative of the famous northern lion’s mane. The sting is usually moderate, but its many long, fine tentacles can cover a large area of skin.

What it looks like

A broad, flat yellowish to orange-red bell with a lobed edge. Beneath it hang eight dense bundles of very fine, hair-like tentacles and folded, curtain-like oral arms.

Size: Bell usually 10–30 cm; tentacles can be several times longer.

Where and when in Thailand

Recorded in the Gulf of Thailand, including around Koh Tao and Koh Phangan, where divers see it.

Gulf of Thailand

The sting

Burning, redness and an itchy rash where tentacles touched. Whole-body reactions are rare and mostly follow large stings.

First aid

📞 Emergency medical services in Thailand: 1669

Leave the water, rinse with seawater and remove tentacles without rubbing. For pain, use hot water around 45 °C for 20 minutes or a cold pack. See a doctor for large stings or if you feel unwell.

Lookalikes

Sea nettle — reddish-brown stripes on the bell and fewer tentacles along the edge.

Did you know

• Its tentacles grow in eight bundles and can number in the hundreds.
• Juvenile fish often shelter under its bell.

Also called: Lion’s mane, Hair jelly