A very rare cold-water loving Leopard fish has been caught off Rockall by a Donegal fishing vessel.

The Leopard fish, also known as a spotted Wolffish (Anarhichas minor), swims in deep water across parts of the Arctic Ocean and the North Atlantic between northern Russia, Scandinavia and Nova Scotia, Canada.

The 5.9-kilo specimen was landed in Greencastle by the Donegal fishing vessel MV Foyle Warrior.

Galway fish merchant Stefan Griesbach contacted rare fish expert Declan Quigley after he spotted it in the box of fish from Greencastle, and knew it was significant.

The Leopard fish has been declared a threatened species in Canada, but does not have international protection status.

It is generally found much farther north, and in deep cold water, Quigley has said.

From his knowledge, there are only two records this far south, both off Scotland.

The two previous records are from the North Sea, Quigley said – off Aberdeen in October 1892, and off St Abbs Head, Berwickshire in June 1993, which seems to be the most southern record in Europe.

He said the fish may be this far south due to melting glaciers, or may be adapting to warmer sea temperatures.

He said he came across one report based on human observation during a scuba-diving event in June 2016 off Tory Island, Co Donegal, but said it was an unconfirmed identification.

The Leopard fish feeds off crustaceans and molluscs, primarily, while it will also eat smaller fish, seaweed and tube worms.

The fish is slow-growing, maturing at around seven years of age and can live up to 21 years.

"They are nice fish to eat - I often had them for dinner during my frequent trips to Norway about 20 years ago,” Quigley said.

“ I also remember noting that the chairs in the Norwegian Embassy in Dublin were upholstered with Anarhichas minor skin!," he said.

Griesbach displayed the fish on his Gannet Fishmongers stand in the Galway market on Saturday.

He plans to freeze it for taxidermy, and to donate it to the Natural History Museum of Ireland in Dublin.

“I might have got 30 euro for this fish which would have made no sense, and this is a much better idea,” Griesbach said.

“Maybe the museum will have a little plaque with my name for my grandkids to see....”