British tourists heading to Croatia's popular Balkan country were urged to stay vigilant when visiting the beach due to invasive species packed with painful, dangerous stab wounds. Previously, only sporadic appearances were made, but Pterois Miles was firmly established in the Adriatic Sea as of 2024, according to marine experts at the Institute of Marine Fisheries at Split.
According to Jutarnji listthe Institute has confirmed that the species, also known as the common lionfish, is currently permanently resident of the Balkan region. Between June 2024 and January 2025, 122 demon fire sightings were recorded along the East Coast, highlighting the extent of the rapid spread of the species.
Most observations were recognized near the picturesque island of Lastovo and Vis. I am particularly concerned about the fact that Vis Island takes pride in the perfect beach with countless postcards, including silver and Tepluš. It was in the area around Dubrovnik that recorded the most observations along the mainland coast. This is the area where we stayed in 2024 for a total of 4.2 million overnights and saw around 335,000 in April 2025 alone.
“It's particularly interesting to note that demon firefish were discovered even in winter months, including shallow bays and relatively low temperatures,” the researchers noted. “The environmental conditions in the Adriatic Sea, particularly the central and southern parts of the country, clearly do not pose obstacles to this species.”
Experts highlight the risks to human health, as demonic firefish stings can be dangerous if left untreated.
Normal lionfish are rayed fish species that grow naturally in the West Indo-Pacific region. It varies in colour from reddish to tan or gray, with numerous thick, dark vertical bars on the head and body. The length of the fish can grow to 14 inches (35 cm) and has a dorsal fin with 13 long strong spines and several soft rays.
Finn spines are highly toxic and have caused death in humans in several reported cases. Fatal stab wounds are rare, but can cause extreme pain, vomiting, cramps, minor paralysis and difficulty breathing.
Therefore, immediate emergency medical procedures are highly recommended even for healthy adults who have been stabbed. Some people are more sensitive to poison than others after being stabbed, and symptoms and reactions to venom vary in severity from person to person.
Experts also warned that species could threaten native fish species and destroy the balance of marine ecosystems. In response to the threat, scientists included mitigation strategies in their research. These include the potential removal of species, particularly from protected marine regions.
