Canary Islands warning as Tenerife beaches fly purple flag amid venomous sea slug alert

The detection of several specimens of the venomous "blue dragon" sea slug - Glaucus atlanticus - has resulted in the council in announcing the raising of a purple flag at two of its popular to signal the presence of harmful marine wildlife.

The decision made by the Council is aimed at alerting the public to the potential danger posed by the blue dragon at El Médano and Leocadio Machado beaches.

The marine species, known for its striking appearance, carries toxins that can cause severe skin irritation, redness, swelling and upon contact.

A yellow flag is already in place - meaning swimming is permitted but caution is advised.

The council advises the public to avoid entering the water and to follow all instructions provided by local authorities. Officials have assured that updates will be provided and beach access will be deemed safe again once the threat subsides, according to .

The creatures are typically found floating on the ocean's surface in warm and temperate waters. They use the ocean currents and wind to move around.

While they are more common in certain parts of the world including and , sightings along other coastal regions, such as the , have also been reported.

The blue dragon is a small but visually striking species of marine mollusc - commonly known as a type of sea slug. It has an eye-catching blue and silver body with delicate wing-like appendages (cerata), giving it a dragon-like appearance. It is small, usually around three centimetres.

The blue dragon does not produce its own venom. Instead, it feeds on venomous creatures like the Portuguese man of war (a jellyfish-like organism) and stores the venom in its own body, specifically in the tips of its cerata.

When threatened or touched, it can release the venom, which is often more concentrated than the original source, causing painful stings in humans.

Though fascinating to observe, the blue dragon is best appreciated from a distance to avoid adding a rather painful element to one's holiday to Tenerife.