Belut

Monopterus albus

Quick Facts

Scientific name Monopterus albus

Other names Asian Swamp Eel

Size Up to 1 m (3.2 ft)

Weight Up to .5 kg (1.10 lb)

Distribution

Habitat & AU Distribution Fresh & brackish waters in muddy swamps, ponds, marshes & lakes

Depth Range 0 - 5 m (16 ft)

Interesting Info

Belut are native to Asia, but in Australia they are considered non-native introductions, sometimes appearing in northern Queensland wetlands.
The Belut is not a “true eel” but a type of swamp eel. Unlike moray eels or freshwater eels, it belongs to its own family of air-breathing fishes.
Its body is long, smooth, and snake-like, usually brown to dark olive, with no scales. Adults often reach 40–70 cm (16–28 in) but can grow over 1 m (3.3 ft).
They are highly adaptable and live in muddy rivers, swamps, rice paddies, and drainage canals, often burying themselves in soft sediment.
They are opportunistic carnivores, feeding at night on worms, insects, small fish, shrimp, and even frogs.
One of their most unusual traits is the ability to breathe air through their skin and mouth lining, allowing them to survive in muddy, oxygen-poor water.
They are known for their resilience — Belut can survive months without water by burrowing deep into wet mud during droughts.
Unlike most fish, Belut change sex during their lifetime. Many start as females and later transform into males, depending on population dynamics.
Breeding usually happens in warm, wet seasons. Males build a bubble nest or burrow where females lay eggs, which the male then guards.
In their native range, they are an important food fish, especially in Southeast Asia, where they are sold in markets and used in traditional dishes.
They can live for around 5–10 years in the wild, although this varies depending on environmental conditions.

Species Interaction

Minimal Species Contact

In Australia, Belut are rare and elusive, with most people never encountering them. They are not targeted for fishing here, and if found, they are usually considered more of an introduced oddity than a species of interest.

Scientific Classification

Kingdom: Animalia

Phylum: Chordata

Class: Actinopterygii

Order: Synbranchiformes

Family: Synbranchidae

Genus: Monopterus

Species: Monopterus albus

Conservation Status

The conservation status of the belut or Asian swamp eel is currently listed as “Least Concern” by the International Union for Conservation of Nature (IUCN). It is considered an invasive species in Australia and is not tracked here.

Fish Taste Quality

Belut are highly valued as food in Asia, where it is considered nutritious and tasty. In Australia, however, it is not eaten and is more often seen as a potential pest species than a food source.

Taste Rating: 3.5/5