Tanglouse, a freshwater fish belonging to the family Pistacidae, mainly comes out at night and feeds on small fish and shrimps.

The body of the pond lice is elongated, about 14cm long.

The front part is flat and the back part is flat. The head is flat and wide, the top is covered with skin, and the back of the skull protrudes to form a triangle with a round end. The mouth is wide, the lower position, the kiss is wide and short, and it is prominent. Small eyes with movable eyelids. There are 2 nostrils on each side, and the anterior nostril is a short tube near the snout. The upper stool protrudes. The lip is thick and the lip groove is obvious. Teeth are small.

4 pairs of whiskers: maxillary whiskers 1 pair, the longest, nasal whiskers 1 pair, mandibular whiskers, 2 pairs, slightly shorter, and slender gill rakes.

Dorsal fin 58-62, without spines, is very long at the base and connected with caudal fin at the end.

Pectoral fin I, 7-8, round, with 1 spines. Abdominal fin 6, reaching the starting point of gluteal fin.

The gluteal fin 39-43, starting from the anus, is very long at the base, and the end is opposite to the end of the dorsal fin. The caudal fin is circular and fan-shaped.

The body is smooth and scaleless, with lateral lines. The body is brown and black, and the abdomen is light. Each fin is grayish black.