Toxic Jellyfish Alert Issued in Phuket as Authorities Urge Caution

Thai authorities have issued a public warning after a large concentration of venomous “fire jellyfish” was discovered in the waters around Koh Aeo in Phuket.

Deputy Prime Minister and Minister of Natural Resources and Environment Suchart Chomklin announced the alert on March 30, urging residents, tourists, and marine operators to exercise caution and avoid contact with the jellyfish.

High concentration detected

According to the Department of Marine and Coastal Resources (DMCR), the jellyfish were found in unusually high numbers — around 100 individuals per square metre. They were observed floating near the surface at depths of approximately 3 to 5 metres.

The species identified belongs to the Pelagia genus, commonly known as fire jellyfish, with an average size of 2–3 centimetres. Officials noted that calm sea conditions likely contributed to their clustering.

Health risks and precautions

Contact with these jellyfish can cause immediate pain, burning sensations, skin irritation, and red rashes. Authorities strongly advise avoiding direct contact during swimming or other sea activities.

In case of a sting, the DMCR recommends pouring vinegar over the affected area continuously for at least 30 seconds and seeking medical attention as soon as possible.

Additional warning in Similan Islands

Separately, a temporary swimming ban has been introduced in parts of the Similan Islands National Park in Phang Nga after another species — the “Blue Button” jellyfish (Porpita porpita) — was found along the shoreline.

This jellyfish, recognizable by its bright blue color and disc-shaped body with trailing tentacles, typically drifts with ocean currents before washing ashore.

Although its sting is less dangerous than that of box jellyfish, it can still cause discomfort, including burning sensations, swelling, itching, rashes, or small blisters.

Authorities continue to monitor the situation and advise the public to remain vigilant while visiting affected coastal areas.