09-15-2025

Three new species of snailfish discovered in the deep Pacific Ocean

Earth.com staff writer

In 2019, a Monterey Bay Aquarium Research Institute (MBARI) dive turned up something no one recognized: a small, bubblegum–pink snailfish cruising just above the seafloor more than two miles down.

A research team led by the State University of New York at Geneseo has confirmed that the mystery fish is a new species to science and has given it a name as memorable as its look: the bumpy snailfish (Careproctus colliculi).

MBARI Senior Scientist Steven Haddock, who led the expedition that filmed and collected the fish, sees this as exactly why sharing deep-sea data matters.

“We welcomed the opportunity to expand our understanding of life in the deep ocean, especially since documenting deep-sea biodiversity is critical to detecting any changes that may be occurring in this environment,” he said.

Adapted to the deep sea

Snailfishes (family Liparidae) are shape-shifters of the oceans, with more than 400 known species living everywhere from tidepools to trenches.

Many carry a suction disk on their bellies – handy for clinging to rocks, seaweed, or even hitching rides on larger animals. At depth, their bodies tend toward jelly-soft and loosely skinned, an anatomy built for cold, crushing pressure and perpetual night. A snailfish, in fact, holds the record for the deepest-dwelling fish ever seen.

Those extremes are what fascinate SUNY Geneseo biologist Mackenzie Gerringer, who studies how deep-sea fishes make a living under conditions that would crush almost anything else.

“The deep sea is home to an incredible diversity of organisms and a truly beautiful array of adaptations,” she said. “Our discovery of not one, but three, new species of snailfishes is a reminder of how much we have yet to learn about life on Earth and of the power of curiosity and exploration.”

One dive, three new snailfish species

Haddock and colleagues spotted the bumpy snailfish during a cruise aboard MBARI’s retired research vessel Western Flyer. They used the remotely operated vehicle (ROV) Doc Ricketts to explore the outer reaches of Monterey Canyon about 62 miles off central California.

At 10,722 feet, a small pink fish swept past the cameras. The team collected the adult female – 3.6 inches long – for careful study back on shore.

That specimen joined two other puzzling finds from 2019. Researchers collected a pair of unusual snailfishes using the submersible Alvin. The dive took place near Station M, MBARI’s long-running abyssal study site around 13,100 feet down.

Together, the trio became the centerpiece of a taxonomic investigation by scientists from SUNY Geneseo, the University of Montana, and the University of Hawaiʻi at Mānoa.

The result is a three-for-one. Alongside Careproctus colliculi, the team formally describes the dark snailfish (Careproctus yanceyi) and the sleek snailfish (Paraliparis em). Each carries a distinct set of traits.

The bumpy snailfish is unmistakably pink, with a rounded head and prominent eyes. It also has broad pectoral fins with elongated upper rays and textured skin that inspired its common name.

The dark snailfish is, as advertised, jet black, with a rounded head and horizontal mouth. The sleek snailfish lacks a suction disk. Its body tapers into a long, laterally compressed, black form capped by a sharply angled jaw.

Naming life from the deep

Proving a species is new takes more than a striking color. The team combined high-resolution imaging and genetics to make its case. They used microscopy and micro-CT (micro–computed tomography) scans to map bones and soft tissues, and DNA sequencing to place each fish on the Liparidae family tree.

Subtle measurements – fin ray counts, jaw angles, body proportions – stacked up with genetic differences to separate the newcomers from lookalikes.

In a nod to place, the species name Paraliparis em honors Station M and the community of programs and people behind it. Their 30-year record has reshaped how scientists understand abyssal ecosystems and their links to climate.

Tracking a deep-sea snailfish mystery

So far, Haddock’s 2019 encounter remains the only confirmed sighting of the bumpy snailfish, leaving its true range a mystery. But MBARI’s vast video archive may hold more clues.

A 2009 dive off Oregon shows a pink snailfish that could be C. colliculi – a clip previously logged as the related bigtail snailfish (Osteodiscus cascadiae). Re-examining older footage with fresh eyes is a quiet superpower of long-term ocean observatories.

Why naming species matters

New species descriptions can sound esoteric, but they are the scaffolding of conservation and climate science.

Without a name and a diagnostic description, a species effectively doesn’t exist on paper. This absence makes it difficult to track shifts in distribution or declines in abundance. It also hinders recognition of changes in life history as deep-sea environments warm and acidify.

They also spotlight the tools that make discovery possible. ROVs like Doc Ricketts, deep-diving submersibles like Alvin, and time-series sites like Station M give researchers the repeated, close-up looks that the deep sea has long resisted.

The bumpy snailfish exists in the literature because a camera happened to be rolling in the right place at the right time. A specimen was also collected gently enough to survive the trip to the lab.

Partnership fuels ocean science

MBARI’s approach – openly sharing dives, specimens, and know-how – helped turn a curious pink fish into a formal snailfish species.

That pipeline, from video archive to taxonomic paper, is becoming more important as interest grows in activities like deep-sea mining. Knowing who lives on the abyssal plain is the first step toward protecting it.

This encounter is the only confirmed observation of the bumpy snailfish. It’s a reminder that even in well-studied waters, one pass of an ROV can change what we think we know.

With every dive and every partnership, the map of deep-sea life gains another dot – and another story worth telling.