Researchers from the University of California in Santa Barbara had to carry out tests on tissue samples to determine the species, which turned out to be something called a hoodwinker sunfish, (or mola tecta).
The weird-looking creature has never been spotted in the northern hemisphere again – in fact, it was only discovered in 2017, by Marianne Nyegaard, from Murdoch University in Australia, who gave it the name ‘hoodwinker’ as it has been so elusive for so long.
The 7ft-long fish washed up on Coal Oil Point Reserve last month and photos of the find were shared on social media, with experts from the University of California and staff at the reserve worked together to get to the bottom of the mystery.
A spokesperson from the University said: “There are rare finds, and then there are out-of-nowhere, first-ever discoveries that send scientists’ hearts aflutter.”
Thomas Turner, an evolutionary biologist who snapped the pics, said: “It’s the most unusual fish you’ve ever seen.
“It has no tail. All of its teeth are fused, so it doesn’t have any teeth. It’s just got this big round opening for a mouth.”
Nyegaard was sent a photo of the ‘mysterious fish’ by fellow expert Ralph Forster and says she was instantly curious.
She said: “I thought that the fish surely looked an awful lot like a hoodwinker, but frustratingly, none of the photos showed the clavus (a rounded rudder) clearly.
“And with a fish so far out of range, I was extremely reluctant to call it a hoodwinker without clear and unambiguous evidence of its identity.
“I just couldn’t be sure due to pixellation and kept thinking I was totally being hoodwinked by this stranded sunfish.”
Speaking to CNN she said this was the first time the fish had been spotted in the northern hemisphere – with previous sightings near to New Zealand, Australia, Chile and South Africa.