SWIMMERS have been warned to take care after a local diver spotted a poisonous fish off the coast of Greystones.
Brendan Moran (50) and his pal Dave Kerr were diving in shallow water when they caught sight of a giant venomous scorpion fish.
Mr Moran, who has over 800 dives behind him, said the creature's size surprised him.
"It's the biggest scorpion fish I have come across in Irish waters," he told the Herald.
Normally, they can be held in the palm of a hand but this one was over a foot long, said Mr Moran.
A sting from the dorsal fin, or its side fins, could be fatal to a small child or elderly person, he added.
"Anyone I met I told about it. I alerted the mayor of Greystones Ciaran Hayden as well," the IT consultant from Bray said.
He warned that the pain from a sting is "excruciating" and can be "severely incapacitating" for swimmers.
"I have been diving for 20 years and I have never seen that size (in Irish waters). Only in the Red Sea have I seen them that size," Mr Moran said.
He has "no idea" why such a large one was off the Co Wicklow coast.
It was hiding in the undergrowth before he saw it and started filming.
Mr Moran, who lives in Loreto Grange and is a member of the Wicklow Aquanauts club, said swimmers should never touch it.
He has dived all over the world and always carries a waterproof camera when he goes out.
During the summer, he goes scuba diving several times a week and last year managed to capture footage of a 10-foot long red jellyfish.
A sting from a scorpion fish can be very serious. In 2005, an Englishman nearly died when he was stung by a scorpion fish while on holiday on the Greek island of Rhodes.
A rare allergic reaction to the venom meant that he was just minutes from death.
However, he managed to get medical attention in time.
If you are stung, the advice is to submerge the wound under very hot water for as long as possible and seek medical assistance.