Common names: carp exhibition, roe deer, etc. Long, slightly flat. The hypopharyngeal teeth are molars. The base of dorsal fin is longer. Both dorsal fin and anal fin have thick, serrated spines. Sideline scale 34 ~ 40. External gill harrow 18 ~ 24. Mouth position, horseshoe shape, tentacles 2 pairs, the latter pair is twice as long as the former pair. The back of the body is pure black, and it is nearly golden yellow below the lateral line. The scales are large and thick, and the caudal fin has three spines, 17- 19 fin. Finally, a single anal fin is bony, with a serrated back and four tentacles. 17-20 branch dorsal fin strip.

The bottom fish have strong adaptability, and most of them live in water with soft bottom and aquatic plants. Swimming is slow in winter and overwinters at the bottom of deep water. Omnivorous fish mainly eat benthos, such as snails, clams, clams and aquatic insects larvae, and also eat a considerable number of higher plants and filamentous algae. The requirements for food are not strict, and vary according to different water bodies and different seasons. In China, the age of sexual maturity is generally early in the south and late in the north, generally around 2 years old, and there are regional differences in spawning seasons. Generally, around Tomb-Sweeping Day, they breed in places where grass grows in rivers and lakes, and lay eggs in batches. The eggs are sticky and develop on aquatic plants. April to May is the peak season; It is cold in the northeast, and spawning begins in June. The number of fertilized eggs varies greatly, ranging from more than 8 thousand to more than 2 million. When the water temperature is 25℃, fry can hatch in four days. Strong adaptability, cold resistance, alkali resistance: hypoxia resistance. Can live in all kinds of waters. It is a widely distributed fish, with large size and fast growth, and the highest total output of freshwater fish.

Carp farming has a long history. Due to different geographical distribution, after long-term artificial and natural selection, there have been group differences, and many breeding varieties have been cultivated, such as red carp from Jiangxi and Zhejiang, which are all excellent varieties. In addition, group carp, mirror carp, scattered mirror carp, abundant carp, purse red carp, Xingguo red carp, Wan 'an glass red carp, Song He carp, Furong carp and koi fish are all carp varieties.

Because of its strong adaptability and wide source of fry, people like to eat carp, which is widely used as ponds, cages and flowing water culture objects, and is also raised in rice fields in many areas, with good returns. According to people's habits, the individual weight of listed commercial carp should be 0.5- 1 kg.