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Chauliodus sloani

Sloane's viperfish

Deep-sea dragonfish with huge teeth and light organs

Photo: Gervais et Boulart, Public domain, via Wikimedia Commons

Sloane's viperfish is a predatory mesopelagic fish found in tropical and temperate oceans worldwide. It uses bioluminescence for camouflage and possesses hinged jaws with large teeth to trap prey.

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  • Jaw opens 90 degrees to catch large prey
  • Uses light organs for counter-illumination camouflage
  • Found in Atlantic, Indian, and Pacific Oceans
  • Teeth form a cage to trap smaller organisms

What it is

Sloane's viperfish is a deep-sea dragonfish belonging to the genus Chauliodus. It features a forked caudal fin, an adipose fin, and a dorsal fin positioned just behind the head. The body is covered in a thick, transparent gelatinous casing, and its scales are poorly ossified. Unlike many surface fish, it lacks a gas-filled swim bladder. Its most striking feature is a set of enormous, fixed teeth that form a cage when the jaw closes.

Where it lives

This species inhabits tropical and temperate waters across the globe. It is widespread in the Atlantic Ocean, particularly between 35°N and 55°N, with peak abundance near 45°N. Populations also exist in the western Mediterranean Sea, the Indian Ocean, and the Pacific Ocean. In the Arabian Sea, it is found primarily south of 10°N. Temperature limits its vertical distribution in the water column.

How it lives

As a specialist predator, it consumes lanternfishes, other bony fishes, and crustaceans. It likely lures prey using its photophores or by dangling a long dorsal ray. The fish can open its mouth up to 90 degrees to capture prey up to 63 percent of its own size. Smaller individuals eat proportionally larger prey than adults. Feeding occurs opportunistically without a specific diurnal pattern, allowing the fish to maximize energy efficiency.

Breeding and life cycle

Female Sloane's viperfish reach sexual maturity when they grow between 133 and 191 millimetres in length. Males are believed to mature at slightly smaller sizes. Specific details regarding spawning seasons, egg laying, or larval development are not provided in the available records.

Sloane's viperfish
A drawing made by EveryFish from what this page says. It is a diagram, not a picture of the real fish.

Fish and people

The species serves as prey for larger marine animals. In the central Mediterranean, it forms a primary part of the diet for Atlantic bluefin tuna. Remnants have also been found in the stomachs of pygmy sperm whales and Gervais's beaked whales. Scientists study its unique jaw mechanics and bioluminescent properties for research purposes.

Status and threats

No conservation status is assigned in the provided data. Its wide circumglobal range suggests it is established in multiple ocean basins.

Sloane's viperfish
Photo: Unknown author, Public domain, via Wikimedia Commons

Questions people ask about Sloane's viperfish

How does Sloane's viperfish catch its food?

It unhinges its jaw to open its mouth up to 90 degrees. This allows it to trap prey up to 63 percent of its own body size. It may lure victims using bioluminescent photophores or a long dorsal ray.

Where does this fish live?

It lives in tropical and temperate mesopelagic waters worldwide. You can find it in the Atlantic, Indian, and Pacific Oceans, as well as the western Mediterranean Sea. Temperature restricts its depth range.

What does Sloane's viperfish eat?

It primarily consumes lanternfishes, other bony fishes, and crustaceans. It is an opportunistic feeder that eats large prey rarely to save energy. Smaller individuals often eat proportionally larger meals than adults.

Good reading and sources

Where this page comes from

The facts on this page come from the Wikipedia article "Sloane's viperfish", written by its contributors and used under the CC BY-SA 4.0 licence, and from its Wikidata record (CC0). EveryFish rewrote the text in its own words, with AI assistance, and compares every page with the article to make sure no passage is copied. It may be reused under the same CC BY-SA 4.0 licence with a link back.

It may contain mistakes, and figures change over time. Nothing here is investment or buying advice. If something is wrong, tell us. Last refreshed 2026-11-15.

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Photo credits on this page

The small pictures above come from Wikimedia Commons under free licences. Some are cropped to fit.

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