Asian swamp eel (Monopterus albus) is a freshwater, brackish species recorded in Hong Kong, Singapore, Malaysia. It is mainly found over mud, estuary, at depths of ≥ 3 m. The main season in Hong Kong, Singapore, Malaysia runs all year.
Scientific name: Monopterus albus · Water: Freshwater, Brackish · Season: All year
Size: up to 100 cm
The Asian swamp eel is a freshwater synbranchid, or swamp-eel: an anguilliform fish with no scales and no pectoral or pelvic fins, its gill openings merged into a single slit beneath the head and its fins reduced to a skin fold. It is an obligate air-breather, taking oxygen through the skin and mouth, which lets it live in water far too low in dissolved oxygen for most fish; it hides in mud and bank burrows by day and hunts fish, worms, crustaceans and detritus at night, and in the dry season it burrows into moist earth and survives long periods without water. The species changes sex during its life, and the male builds a floating bubble nest and guards the nest and the young. Malaysians call it belut, also belut sawah or ikan belut. Singapore records it from the reservoirs, canals and wetland mud throughout the island — MacRitchie, Lower Peirce and the Kranji area, as well as Sungei Buloh and Lorong Halus — at any time of year, and in Malaysia from the rice districts and irrigation canals of Kedah, Perak and Selangor's Sekinchan area, the Kelantan paddies of the east coast, and the peat swamps and drains around Sibu and Miri in Sarawak. Because it rarely leaves a burrow it is almost never taken on a lure; a night session with earthworm fished hard on the bottom, or careful work at a known burrow mouth, is the practical approach, and an eel that has taken will wrap itself around snags and has to be walked clear. It is regarded as a strengthening food, keeps market prices high, and stays alive for long periods as long as the skin is kept moist. Most fish run 25–40 cm, with a maximum of about 100 cm. IUCN lists it as Least Concern.
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