Identification
A long eel-shaped body, small eyes and a flattened head distinguish its general appearance. The dorsal and anal fins are reduced to low folds. A single gill opening beneath the head gives rise to the name Onegill Eel. Color can be dark brown, greenish or reddish.
Size and Weight
The reported species maximum is 100 cm total length, approximately 39.4 inches. An Australian account describes fish to 55 cm; that regional figure does not replace the larger species-wide report. A dependable maximum weight was not verified.
Habitat and Natural History
This fish inhabits fresh and brackish water, including swamps and slow river habitats with thick vegetation. Mud and burrows provide shelter. Its ability to breathe air is documented for this species, helping explain its association with stagnant waters.
Avoiding a Common-Name Mix-Up
Monopterus albus is also widely called Asian Swamp Eel. Its invasive history, feeding studies and capture advice should not automatically be assigned to Ophisternon bengalense. A verified species-specific bait recommendation was not established for this profile.
The Onegill Eel
The single opening beneath the head is a useful anatomical clue. Together with reduced fins and an elongated body, it distinguishes this swamp eel’s form from the familiar appearance of many river fishes. Its common names alone are less reliable identifiers.
All Lakes With Asian Swamp Eel
Browse lakes and reservoirs with documented Asian Swamp Eel records, listed alphabetically. Records do not establish current abundance or public access. Check the evidence and managing authority for the water you choose.
No published lakes are currently linked to this species in our confirmed records.