Clarius fuscus is a species of tropical and subtropical small bottom-dwelling fish in the family Clarius fuscus. The body is elongated, the head is flat and oblique, and the rear side is flattened; the back of the head has a bony plate. The snout is broad and short. The anterior nostril is a short tube and the posterior nostril is slit. The upper jaw is more prominent. There are four pairs of whiskers, one pair each of the nose whiskers and the chin whiskers, which are shorter; the upper and lower jaw whiskers are one pair each, which are longer. The body is bare and without scales, the skin is smooth and mucus; the lateral line is straight, extending along the middle of the body to the base of the tail. The base of the dorsal fin is long; the anal fin is the same shape as the dorsal fin, not connected to the caudal fin; the pectoral fin is small, but has a thick spine, and its inner edge is serrated. Body yellow-brown or gray-black, belly gray-white; sometimes there are 10 longitudinal stripes with 5-6 small white spots on the side of the body.

Clarius fuscus is a tropical and subtropical small benthic fish. Often inhabits overgrown rivers, ponds, ditches, swamps and caves in rice fields or in the dark. Sexually gregarious, gathering dozens or more together. Because a gill cavity has auxiliary respiratory organs. Therefore, the adaptability is very strong, and the survival time is longer after leaving the water. Feeds on aquatic insects and certain larvae, shrimps, oligochaetes, small mollusks and small fish. Clarius fuscus is distributed in China (Guangdong, Guangxi, Yunnan, Guizhou, Hong Kong, Taiwan), Laos, and Vietnam.
Clarius fuscus is a tropical and subtropical small benthic fish. Often inhabits overgrown rivers, ponds, ditches, swamps and caves in rice fields or in the dark. Sexually gregarious, gathering dozens or more together. Clarius fuscus has an auxiliary respiratory organ in a gill cavity. Therefore, the adaptability is very strong, and the survival time is longer after leaving the water. Feeds on aquatic insects and certain larvae, shrimps, oligochaetes, small mollusks and small fish.