Watch: Scientists film the world's deepest fish off Japan

Scientists in search of deep-sea creatures around the world filmed what has been deemed the "world’s deepest fish." 

The fish, an unknown snailfish, was filmed at more than 27,000 feet below the surface, researchers said. It was later certified as the deepest fish in the world by Guinness World Records

The finding was part of a two-month expedition beginning in August 2022 to the deep trenches around Japan in the North Pacific Ocean, led by a team of scientists from the University of Western Australia (UWA) and Tokyo University of Marine Science and Technology. 

Specifically, the mission was to explore the Japan, Izu-Ogasawara, and Ryukyu trenches, which are 8,000 meters (26,247 feet), 9,300 meters (30,512 feet) and 7,300 meters (23,950 feet) deep respectively.   

In the Izu-Ogasawara Trench, south of Japan, the team filmed the deepest record of a fish, the unknown snailfish species of the genus Pseudoliparis, at a depth of 8,336 meters (27,349 feet) on Aug. 15, 2022, according to a statement from UWA.


Images of the snailfish alive from 7500-8200 meters in the Izu-Ogasawara Trench. (Credit: Provided / University of Western Australia)

Days later, the team also collected two fish in traps in the Japan Trench at 8,022 meters (26,319 feet) deep.

"We have spent over 15 years researching these deep snailfish; there is so much more to them than simply the depth, but the maximum depth they can survive is truly astonishing," UWA Professor Alan Jamieson, founder of the Minderoo-UWA Deep Sea Research Centre and chief scientist of the expedition, said in a statement.

"In other trenches such as the Mariana Trench, we were finding them at increasingly deeper depths just creeping over that 8,000m mark in fewer and fewer numbers, but around Japan they are really quite abundant," Jamieson added.

The team said that the world’s deepest fish ever found was an "extremely small juvenile." They added that snailfish tend to be the opposite of other deep-sea fish, where the juveniles live at the deeper end of their depth range.

Jamieson said that until this expedition, "no one had ever seen nor collected a single fish from this entire trench."

The snailfish, Pseudoliparis belyaevi, were the first fish to be collected from depths greater than 8,000 meters, the UWA said, and have previously only ever been seen at a depth of 7,703 meters in 2008.

This story was reported from Cincinnati.