A huge rare fish has been discovered on a beach in the US (PHOTO)

A huge sunfish, which lives in temperate waters in the Southern Hemisphere, has washed up on the northern Oregon coast, Phys.org reports.

According to a press release from Seaside Aquarium, the 2.2-metre-long sunfish appeared on a beach in Gearhart on Monday 3 June. As of Friday, the fish was still on the beach and can remain there for weeks because of its tough skin, which is difficult for scavengers to penetrate.

Photos from the aquarium show the flat, round, grey fish lying on its side on the sand. Additional shots with a truck parked nearby emphasise its impressive size.

The unusual sighting caused a stir on social media, prompting New Zealand researcher Marianne Niegaard, who studies these fish, to contact the aquarium. After studying the photos, Niegaard confirmed that it was indeed a hoodwinker sunfish (Mola tecta), which is rarer than the common oceanic sunfish. She speculated that it may be the largest specimen ever recorded.

Niegaard's 2017 study, based on genetic sampling and observations, identified Mola tecta, as a separate species from the common sunfish, Mola mola. The term "tecta" is Latin for "hidden" or "camouflaged," indicating the new species was "hiding in plain sight," as the aquarium noted.