# Viperfish (*Chauliodus sloani*)

> The Sloane's viperfish (Chauliodus sloani) is a fang-toothed deep-sea predator with a hinged skull for swallowing large prey. Adults reach 30 cm and are Least Concern.

- **Category:** Fish
- **Conservation status (IUCN):** Least Concern
- **Range:** Deep oceans worldwide.
- **Canonical page:** https://globalanimalguide.org/animals/viperfish/
- **Last reviewed:** 2026-07-16

## Scientific classification

- **Kingdom:** Animalia
- **Phylum:** Chordata
- **Class:** Actinopterygii
- **Order:** Stomiiformes
- **Family:** Stomiidae
- **Genus:** Chauliodus

## Facts at a glance

| Attribute | Value |
| --- | --- |
| Scientific name | Chauliodus sloani |
| Diet | Carnivore |
| Habitat | Mesopelagic and bathypelagic zones |
| Lifespan | 8–12 years |
| Weight | 0.02–0.05 kg |
| Top speed | up to 3 km/h |
| Conservation status | Least Concern (IUCN) |

## Needle teeth and hinged skull

Enormous fangs fold inward; the skull rotates to swallow fish nearly as long as the viperfish. Green photophores along the side may lure prey in darkness.

## Fish and squid in the midnight zone

Ambush and pursuit in mesopelagic and bathypelagic depths. Vertical migration places them in feeding layers at night.

## Deep oceans worldwide

Chauliodus sloani occurs across Atlantic, Pacific, and Indian Ocean deep basins. Larvae rise nearer surface before adopting deep adult habits.

## Abundant deep predator

Least Concern with vast habitat and no fishery. Night trawls regularly capture viperfish where few other vertebrates venture.

## Frequently asked questions

### How long are viperfish teeth?

Fangs can exceed half the fish's head length — so long they fold beside the brain.

### Do viperfish light up?

Yes — photophores along the body may attract prey in the black bathypelagic zone.

### How deep do viperfish live?

Hundreds to thousands of metres down, rising higher only at night to feed.

### Can viperfish swallow big fish?

A hinged skull and elastic stomach let them take prey nearly their own length.

### Are viperfish dangerous to humans?

No — they live in deep water and are small; contact with divers is essentially nil.

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Source: Global Animal Guide (https://globalanimalguide.org/animals/viperfish/). Licensed CC BY-NC 4.0 — free for non-commercial reuse with attribution.