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Coelacanth

The coelacanth is a deep-sea lobe-finned fish best known for being a “living fossil,” with a fossil record extending back more than 400 million years.

By Ethan Anderson| Reviewed by Olivia Bennett, Standards & Fact-Checking Lead| Updated July 26, 2026|2 min read| Fact-checked

The coelacanth is a deep-sea lobe-finned fish best known for being a “living fossil,” with a fossil record extending back more than 400 million years. Only two living species are known today, both in the genus Latimeria, found in the western Indian Ocean and near Sulawesi, Indonesia.

Evolution and fossil record

Coelacanths have one of the oldest fossil records among living vertebrates, with fossils dating to the Devonian. Their lineage is often cited as important for understanding the evolution of lobe-finned fishes and the ancestry of tetrapods.

Living species and distribution

Only two living coelacanth species are known, both in the genus Latimeria. They are found in deep waters off the Comoros and other parts of the east African coast, and in Indonesian waters near Sulawesi.

Habitat and behaviour

Modern coelacanths live in deep marine environments, often around steep volcanic slopes and submerged caves. They are mostly nocturnal and feed slowly on fish and cephalopods.

Discovery and conservation

The discovery of a living coelacanth in 1938 overturned the assumption that the group had gone extinct millions of years earlier. Today, coelacanths are rare and protected, with conservation status varying by species.

Key facts

  • The earliest coelacanth fossils date to the Devonian period, about 420 million years ago.
  • Two living species are recognized: the West Indian Ocean coelacanth and the Indonesian coelacanth.
  • Coelacanths are lobe-finned fish and are among the closest living relatives of tetrapods.
  • They typically live in deep waters, sheltering in caves by day and feeding at night.
  • The West Indian Ocean species was long thought extinct until a living specimen was caught in 1938.
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Canadian context

Coelacanths are mainly of scientific and educational interest in Canada, especially in zoology, evolutionary biology, and museum collections.

Frequently asked questions

How many living coelacanth species are there?
There are two known living species, both in the genus Latimeria.
Where do coelacanths live?
They live in deep waters near the Comoros Islands, along parts of the east African coast, and near Sulawesi, Indonesia.
What do coelacanths eat?
They feed mainly on fish and cephalopods such as squid, cuttlefish, and octopus.
Why are coelacanths called living fossils?
Because their lineage is very ancient and they resemble fossil forms known from hundreds of millions of years ago.
When was a living coelacanth first discovered?
A live coelacanth was first caught in 1938 off East London, South Africa.

References

  1. Smithsonian Oceanhttps://ocean.si.edu/ocean-life/fish/coelacanth
    Supports: Two living species; fossil age; habitat; diet; distribution.
  2. Encyclopaedia Britannicahttps://www.britannica.com/animal/coelacanth
    Supports: Coelacanth as genus Latimeria; living lobe-finned fishes.
  3. Natural History Museumhttps://www.nhm.ac.uk/discover/coelacanths-the-fish-that-outdid-the-loch-ness-monster.html
    Supports: Discovery history; habitat; size; conservation notes.
  4. Virginia Institute of Marine Sciencehttps://www.vims.edu/research/facilities/fishcollection/_archive/highlights/coelacanth.php
    Supports: 1938 rediscovery; living fossil status; fossil history.
  5. Australian Museumhttps://www.australian.museum/learn/animals/fishes/coelacanth-latimeria-chalumnae-smith-1939/
    Supports: Distinctive anatomy; intercranial joint; classification.