Pseudoliparis swirei was captured at 7,966 metres, a depth that may represent a record for a fish caught on the seafloor.
The specimen came from the Mariana Trench during the work that led to the species’ formal description. Researchers collected 37 P. swirei specimens from depths between 6,898 and 7,966 metres, making the capture especially important for documenting life in the hadal zone.
The wording “possible record” matters: the figure refers to a fish physically captured from the seafloor, not merely seen by a camera. Those categories can produce different records. In 2022, an unidentified juvenile snailfish was filmed deeper still, at 8,336 metres, in the Izu–Ogasawara Trench.
The Mariana snailfish’s soft body, reduced bony structure and pressure-tolerant biochemistry help explain how it survives at nearly eight kilometres below the surface.