Common name: Freshwater Eels



Freshwater eels belong to the genus Anguilla. They are catadromous, spending most of their lives in freshwater before migrating far from home to breed in tropical waters.

Like all true eels, they have a distinct transparent leptocephalus larval stage.

Cite this page as:
Dianne J. Bray, Freshwater Eels, ANGUILLIDAE in Fishes of Australia, accessed 26 May 2017,

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Family Taxonomy

The single genus Anguilla comprises about 20 species, four of which are found in Australian waters.

Family Distribution

Freshwater eels occur in all tropical and temperate oceans, except in the Eastern Pacific along the western coast of the Americas and in the south Atlantic.

Most spend their adult lives in freshwater, migrating to breed in the open ocean. Some Australian species are thought to breed in the Coral Sea northeast of Australia near New Caledonia.

Family Description

Freshwater eels have well-developed jaws, with the lower jaw usually longer than the upper; well-developed pectoral fins; well-separated paired gill openings at the pectoral fin base, well developed eyes; the posterior nostril located in front of eyes. The anus is located slightly in front of the middle of the body.

A single long, low dorsal fin begins well-behind the head; a long, low anal begins just behind anus; the caudal fin is continuous with both the dorsal and anal fins. Body scales are embedded in skin and difficult to detect.

Family Size

Individuals may reach 2 m in length.

Family Feeding

Carnivores - feeding mostly on a variety of aquatic invertebrates and vertebrates, including insect larvae and fishes. They also occasionally take small aquatic birds.

Family Reproduction

The sexes are separate and freshwater eels are egg-layers (oviparous). They have a catadromous lifecycle with adults migrating to the sea to breed. The eggs hatch into transparent leaf-like leptocephalus larvae that metamorphose into elvers or "glass eels".

The elvers migrate to coastal rivers and freshwater streams and dams where they spend up to 10 years before they mature and return to the sea to breed. After entering freshwater, glass eels rapidly develop pigment and remain in freshwater for many years.

As they mature, the eels develop larger eyes and become silvery and migrate back to the sea to breed.

Family Commercial

Freshwater eels are imortant food fishes throughout their range. They are marketed fresh, smoked, canned or freshly cooked, as well as being sold live as glass eels or juveniles for stocking purposes. Eels are exported live and frozen from Australia.

Family Conservation

The conservation status of three species of Anguilla have been assessed by the IUCN (International Union for the Conservation of Nature)

Family Remarks

The larvae are apparently transparent because the red blood cells do not develop until the they transform into glass eels.


Dianne J. Bray

Family Resources

Atlas of Living Australia 

Australian Faunal Directory

CAAB Codes for Australian Aquatic Biota

Catalog of Fishes  

OZCAM – Online Zoological Collections of Australian Museums


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