Meet the fish making headlines in Greece!
- Christina Zantioti
- Jun 16
- 3 min read
Lagocephalus sceleratus is one of the most disruptive invasive species in the Mediterranean. Here is what it is, how it got here, and why scientists are worried.
A fish with no business being here.
If you have been near the Greek coast recently, or following environmental news, you have probably heard about the lagocephalos. Its scientific name is Lagocephalus sceleratus, and it is a silver-cheeked toadfish originally native to the Indo-Pacific.
It does not belong in the Mediterranean. But it is here; it is established, and it is not leaving.
L. sceleratus is a Lessepsian migrant, meaning it entered the Mediterranean through the Suez Canal. The Canal, opened in 1869, created a direct corridor between the Red Sea and the Mediterranean, allowing species that evolved in the Indo-Pacific to move into entirely new waters. L. sceleratus was first recorded in the Eastern Mediterranean in Turkish waters in 2003. Within a few years, it had spread to Greece, Cyprus, Egypt, Lebanon, and Syria. Today it has expanded as far west as the Strait of Gibraltar.
Why it is a problem for fishers.
L. sceleratus is highly opportunistic in its feeding behaviour. It attacks fish that are already caught in nets and on lines, eating or destroying commercial catch before it ever reaches the boat. It also damages the fishing gear itself, cutting through nets and longlines.
The economic consequences are significant. In 2018, it was reported that it represented 4% of the weight of the total artisanal catches. was estimated that Research assessing the impact on small-scale fisheries in Greece estimated losses of up to EUR 6,300 per vessel per year for fishers operating in Crete, where the species is most abundant. Fishers in affected areas have been forced to change their fishing tactics, move to different depths, or avoid certain zones entirely.
This is not a minor inconvenience. For small-scale coastal fishers operating on tight margins, losses at this scale are serious.
The toxin that makes it dangerous to humans.
Beyond its impact on fisheries, L. sceleratus poses a direct risk to human health.
It is a poisonous fish containing tetrodotoxin, or TTX, a potent neurotoxin. TTX is one of the most powerful natural toxins known to science, and there is no antidote. It blocks sodium channels in nerve cells, causing paralysis that can progress to respiratory failure.
The toxin is not destroyed by cooking. It cannot be removed by cleaning or preparation. The species has no immediate economic value for the Mediterranean market precisely because of this; it cannot safely be sold or consumed, and any handling of the fish requires care.
Hospitalisations linked to L. sceleratus have been reported across the Eastern Mediterranean. In some cases, consumption has been fatal.
What does climate change have to do with it?
The short answer: a lot.
L. sceleratus thrives in warm, saline waters. As Mediterranean sea surface temperatures continue to rise due to climate change, conditions in areas that previously offered some resistance to the species are becoming increasingly suitable. Recent modelling work published in 2025 predicts that warming bottom temperatures will continue to support the expansion of L. sceleratus into new parts of the Aegean and beyond.
This is not a species we can simply wait out. The environmental conditions driving its spread are intensifying, not reversing.
What can you do?
If you encounter a lagocephalos:
Do not handle it with bare hands
Do not attempt to eat it under any circumstances
Report sightings to the Hellenic Network on Aquatic Invasive Species, to help researchers track the spread
Citizen observations are genuinely useful data. The more sighting records researchers have, the better they can map the species’ distribution and anticipate where it will appear next.
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