Blue dragon sea slug spotted in Catalonia for first time

A Glaucus atlanticus, also known as a blue dragon sea slug, was spotted on the beach of Tamarit, southern Catalonia, for the first time ever. The venomous animal forced the closure of the beach on Sunday afternoon, as Catalan civil protection services announced.

This is a small venomous animal that stores stinging cells from its predators, which could mean that humans handling the blue dragon could receive a dangerous sting. It feeds on other creatures, including the Portuguese man o' war and other venomous animals.

The potential of the blue dragon's sting depends on the level of venom from the animals it fed of.

The small animal is usually around 3 cm, and it is silvery gray and blue, with dark blue stripes on its head.

Blue dragons are commonly found in tropical and open ocean waters, however, during summer 2025, there were several specimens spotted on the coast of Spain's Lanzarote, and Alicante.

Sunday's is the first time the animal has been spotted off the shore of Catalonia.

Experts believe that the sea surface temperature records are one of the main reasons why the blue dragon species is appearing off the shores of Spain.