Tourists spending their summer holidays along the Croatian coast are being advised to exercise caution because of the increasing presence of lionfish in the Adriatic Sea.
Austrian media have drawn attention to the spread of the invasive species, also known as the devil firefish or red lionfish. Its long spines contain venom, and contact can cause intense pain and other health complications. The warning is particularly relevant for swimmers, divers and fishermen who may encounter the fish in shallow coastal waters.
Lionfish are originally found in the Indo Pacific region and the Red Sea, but they have gradually expanded through the Mediterranean and into the Adriatic. Marine researchers say warmer sea temperatures and favorable environmental conditions have helped the species establish itself along the Croatian coast.
Croatia’s Institute of Oceanography and Fisheries recorded 122 confirmed sightings between June 2024 and January 2025. The largest concentrations were reported around the islands of Lastovo and Vis, while sightings were also recorded near Dubrovnik, Mljet, Korčula, Hvar and other parts of the southern and central Adriatic. Most of the fish were observed at depths of less than 15 meters.
Experts warn that lionfish are not only a concern for people entering the sea. As an invasive predator with few natural enemies in the Adriatic, the species can also threaten native fish populations and disturb the marine ecosystem.
Tourists should not touch or attempt to catch a lionfish, even when it appears inactive or has already been removed from the water. Its spines can remain dangerous. Anyone who is stung should leave the water, seek medical assistance and avoid treating the injury without professional guidance.
The growing presence of lionfish does not mean that the Croatian coast is generally unsafe. Current international travel guidance continues to describe Croatia as a safe destination where visitors should follow normal precautions. The warning is instead a reminder for people enjoying the sea to remain observant and avoid unfamiliar marine animals.
