“Watch Out for the Four!”: Keep Your Eyes Open for Invasive Alien Fish in Italian Waters
Fishermen, divers, and anyone who has observed or caught a lionfish or any of the other three potentially dangerous tropical species—the silver-cheeked toadfish, the dusky rabbitfish, and the marbled spinefoot—in Italian waters are invited to support the “Watch Out for the Four!” awareness campaign. The campaign aims to inform the public about the presence of these invasive species in our seas and encourage the reporting of sightings.
The Italian Institute for Environmental Protection and Research (ISPRA) and the Institute for Biological Resources and Marine Biotechnology of the National Research Council (CNR-IRBIM) in Ancona, in collaboration with the AlienFish project, are relaunching the "Watch Out for the Four!" awareness campaign. The initiative provides practical guidance on how to identify these species, prevent potentially harmful encounters, and contribute to monitoring their spread. Citizens are encouraged to document any sightings with photographs or videos and submit their observations via the dedicated reporting link.
Alternatively, sightings can be reported via WhatsApp at +39 320 4365210, by email at alien@isprambiente.it, or through the Facebook groups Oddfish and Fauna Marina Mediterranea, in collaboration with the AlienFish project, using the hashtag #Attenti4.
The Four Alien Species
Lionfish (Pterois miles) – Having entered the Mediterranean through the Suez Canal, the lionfish was first recorded in Italian waters in 2016. It is considered one of the world's most invasive marine species and is also known for its successful colonisation of large areas of the western Atlantic, where it has caused significant ecological impacts. Although edible, it should be handled with extreme care, as its venomous spines can inflict very painful stings, even up to 48 hours after the fish has died.
Silver-cheeked toadfish (Lagocephalus sceleratus) – Also introduced through the Suez Canal, this species was first recorded in Italian waters in 2013. It is easily recognised by the dark spots scattered across its silvery-grey back. The silver-cheeked toadfish contains a powerful neurotoxin that makes it highly poisonous if consumed, even after cooking. In addition, it has exceptionally strong teeth capable of inflicting painful bites.
Dusky rabbitfish (Siganus luridus) and Marbled spinefoot (Siganus rivulatus) – These two herbivorous species also entered the Mediterranean through the Suez Canal and were first recorded in Italy in 2003 and 2015, respectively. Both are highly invasive and, although edible, possess venomous fin spines that can cause painful injuries, even after the fish has died.
