Swamp eels are freshwater fish, but they are not closely related to other living eels or snake-like marine and freshwater fishes. In addition to the name swamp eel, other English common names used for members of this group of fish include rice eel, rice-paddy eel, and belut. The swamp eel family includes more than a dozen species.
Asian swamp eels may be confused with a number of native animals, including the native American eel, as well as several eel-like amphibians such as sirens and amphiumas. But unlike the American eel, swamp eels do not migrate to the ocean to spawn. The swamp eel has a snake-like body with no noticeable scales or fins. The head is relatively short and the teeth are small and not easily seen. The gill opening forms a V-shape on the lower throat area. The body and head are dark, sometimes dark olive or brown above, and their underside is usually lighter, often light orange. Some are brightly colored with yellow, black, and gold spots over a light tan or almost-white background. The skin produces a thick mucous layer making the eels difficult to hold.