Eels are snake-shaped and cylindrical. The head is thick and the tail is thin, and the body surface has a smooth mucosal protective layer, which is yellowish brown in color. Distributed in Southeast Asia, China, western Korea, southern Japan and other places. Often live in muddy waters such as rice fields, rivers and ponds.

Monopterus albus is slender, cylindrical and snake-shaped, with a body length of about 20~70 cm and the longest length of 1 m, with a flat front and rear part and a pointed tail. The head is enlarged, long and round, and the cheeks are raised.