Black herring, also known as black pomfret, has large scales all over its body. It looks like grass carp, but its scales and fins are grayish black. Hence the name of herring. Scales are large and thick. Its tail is thinner than grass carp. Dorsal fin, pectoral fin, ventral fin and caudal fin are longer and stiffer than grass carp. Black herring is mainly distributed in the plain area south of the Yangtze River in China, and it is rare in the north of the Yangtze River.
Grass carp is also called pomfret, pomfret, grass pomfret, pomfret, grass carp, grass root (northeast), hybrid, black herring and so on. The body is long and "delicate", with a bluish yellow body color and a slightly white abdomen. Scales are large and thick. Its dorsal fin, pectoral fin, ventral fin and caudal fin are smaller and shorter than herring. Rivers and lakes inhabiting plain areas generally prefer to live in the middle and lower layers of water and coastal areas with many aquatic plants.
Silver carp, also known as silver carp, bream, silver carp, silver carp and silver carp, belongs to CYPRINIDAE and is one of the four famous fish. The figure is flat on the side, slightly higher, spindle-shaped, with blue-gray back and white sides and abdomen. The pectoral fin does not exceed the base of the ventral fin.
Bighead carp is also called silver carp, silver carp, silver carp, chub fish, bighead fish, black carp, hemp carp, and some are called male fish. The body is a bit like silver carp, but the head is much bigger than silver carp, so it is also called "chubby fish", which has the nickname of "scavenger in the water" and is one of the four major fish in China.
Extended data:
Black carp, grass carp, silver carp, bighead carp. They all belong to the fish class, CYPRINIDAE. Black herring inhabits the bottom of the water, and its staple food is mollusks such as snails and mussels and aquatic worms.
Grass carp likes to move around the edge of water and feed on aquatic plants. Silver carp inhabits the upper layer of water and feeds on phytoplankton. Bighead carp also likes to move in the upper layer of water, feeding on zooplankton.
From the late Yin Dynasty to the Tang Dynasty, the object of fish farming in China has always been carp. In the Tang Dynasty, because the surname of the emperor was Li, and Li carp was homophone, and "carp" was used as a symbol of the royal family, so it was necessary to avoid "carp", which could not be caught or sold. Whoever is caught and released will be punished by being beaten 60 times. These have been stipulated by law.
In this case, fishermen are forced to find new breeding objects, namely, green grass, silver carp and bighead carp. Because of their different feeding habits and habitat habits, these four kinds of fish are very suitable for mixed culture in a pond, which can make full use of natural bait and water space and have greater breeding benefits.
Therefore, it has become a traditional cultured fish in China. Until today, these four kinds of fish are still the main fish in freshwater fish culture in China. Because they are farmed fish, they are called "four big fish".
Baidu Encyclopedia-Four Big Fish