Fish
Mariana snailfish
Pseudoliparis swirei
Hadal zone
The deepest-living fish ever confirmed, discovered in 2014 and formally described in 2017 in the Mariana Trench, at nearly 8,000 m below the surface.
🗺️ Geographic range
Endemic to the Mariana Trench, in the northwest Pacific.
📊 Population
No estimate available: discovered too recently, and living in an environment completely inaccessible to standard census methods.
Habitat
- Pacific Ocean · Hadal zone · Permanent
🥚 Reproduction
Poorly documented; no precise data on breeding season or frequency is available.
Behaviour
- Diet
- Small crustaceans, notably amphipods, caught on the floor of the trench.
- Hunting
- A discreet predator moving slowly near the bottom, with no known competitor at this depth.
- Communication
- None known.
- Social life
- Sometimes observed in small groups around bait, with no known hierarchy.
Physiology
- Anatomy
- Pale, gelatinous, tadpole-shaped body with unpigmented skin and scales; thin, partly unossified skeleton.
- Respiration
- Gill respiration.
- Vision
- Reduced eyes, adapted to total darkness.
- Adaptations
- Cells saturated with TMAO (trimethylamine N-oxide), a molecule that protects its proteins from being crushed under the extreme pressure of the abyss.
⚡ Its extraordinary abilities
- The deepest-living fish ever confirmed, down to about 8,000 m
- Its cells are protected from being crushed by a molecule (TMAO) that stabilises its proteins under extreme pressure
🏆 Records
Deepest confirmed living fish ever observed
Captured and documented down to about 8,076 m in the Mariana Trench, a record for a fish.
Source: Zootaxa
If you cross paths with this animal…
Risk: None: completely inaccessible without a crewed or robotic submersible.
Behaviour: Discreet, moves slowly near the floor of the trench.
Advice: Discovered too recently, in an environment too extreme, to be observed outside of a scientific expedition.
💡 Did you know?
- Named in honour of Herbert Swire, a naval officer on the 19th-century HMS Challenger expedition, a pioneer of deep-sea exploration.
- Discovered during expeditions in 2014 and 2017 aboard the research vessel Falkor, before being formally described as a new species in 2017.
