Warnings are being issued to swimmers and beach-goers around the West Tamar area after sightings of the potentially deadly blue-ringed octopus.
A photo of the creature has been posted to the Greens Beach Community Facebook page and follows a sighting near Don Heads last month.
Blue ringed octopi have been found on Coastal beaches at Hawley, Penguin and Wynyard in recent summers.
The blue ringed octopus is one of the most venomous of the species.
The creature produces tetrodotoxin or TTX, in its salivary glands, which is 1,000 times more lethal than cyanide.
As little as one milligram can kill a human, with the octopus carrying enough toxin to kill 26 adults.
It grows to around 12 cm in length and is typically found on shallow rocky shorelines in tidal pools and reef flats and out to deeper waters up to 60 metres.
There’s more information at beachsafe.org.au including what to do if you’re bitten by a blue ringed octopus.