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Triplewart seadevil

A deep-sea anglerfish with extreme sexual dimorphism and parasitic males.

Photo: Dr Tony Ayling, CC BY-SA 1.0, via Wikimedia Commons

The triplewart seadevil is a marine ray-finned fish in the family Ceratiidae. It was first described by Theodore Gill in 1883. This species lives in deep oceans worldwide and is known for its unique reproductive strategy.

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  • Only species in genus Cryptopsaras
  • Males parasitize females permanently
  • Bioluminescent lure attracts prey
  • Found in all major oceans
  • Described by Theodore Gill in 1883

What it is

This creature belongs to the order Lophiiformes and the family Ceratiidae. It is the sole member of the genus Cryptopsaras. Females possess an elongated body that is compressed from side to side. They have a large head and a mouth that stands nearly vertical when shut. The skin features hollow spines embedded deeply, with only their tips visible. Adult females are jet black, while juveniles appear dark brown. Three lateral caruncles on the body contain glands that release slime with glowing particles.

Where it lives

These fish inhabit every major ocean across the globe. They dwell at depths between seventy-five and four thousand metres. Most specimens reside in the mesopelagic and bathypelagic zones, specifically between five hundred and twelve hundred fifty metres. Their swimming ability is weak, so ocean currents transport them over vast distances. This dispersal moves individuals from the deep ocean toward shallower waters.

How it lives

Females use a modified spine called an illicium to attract prey. This structure ends in an esca, or lure, supported by a long bone inside a sheath. Muscles control the movement of this bone, allowing it to extend and retract. The esca houses bacteria that produce light, creating a glowing bait. The mouth morphology resembles that of frogfishes, suggesting adaptations for suction feeding through buccal expansion.

Breeding and life cycle

Males are significantly smaller than females, ranging from one to seven point three centimetres. They attach permanently to the female's body, usually on the underside. Tissue fusion binds their mouths and circulatory systems together. The male becomes dependent on the female for nutrients. Females can accept males at a young age, often before twelve months old. Spawning happens multiple times annually, with larvae appearing most frequently in summer.

Triplewart seadevil
A drawing made by EveryFish from what this page says. It is a diagram, not a picture of the real fish.

Questions people ask about Triplewart seadevil

What makes the triplewart seadevil unique?

It displays extreme sexual dimorphism where dwarf males permanently attach to larger females. This parasitic relationship allows the male to receive nutrients directly from the female's bloodstream after tissue fusion occurs.

How does the triplewart seadevil catch food?

Females use a bioluminescent lure called an esca on a modified spine. Bacteria within the lure create light to attract prey. The mouth structure supports suction feeding through extreme buccal expansion.

Where do these fish live?

They are found worldwide in all major oceans. They inhabit depths from seventy-five to four thousand metres, primarily in the mesopelagic and bathypelagic zones between five hundred and twelve hundred fifty metres.

Good reading and sources

Where this page comes from

The facts on this page come from the Wikipedia article "Triplewart seadevil", 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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