Freshwater fish? Broadly speaking, fish that can live in fresh water with salinity of three thousandths can be called freshwater fish. In a narrow sense, it refers to fish that have only "juvenile stage" or "adult stage" in some stages of their life history, or must spend their whole lives in fresh water areas. There are about 26,000 species of fish and 8,600 species of freshwater fish in the world. There are nearly 3,000 species of fish in China, including freshwater fish 1000.

There are more than 26,000 known fish species in the world, which is the largest group of vertebrates, accounting for 48. 1% of the total number of vertebrates. Most of them live in the ocean, and there are about 8600 species of freshwater fish. There are nearly 3,000 species of fish in China, including freshwater fish 1000.

Herring? Black herring is a blue fish, which is mainly distributed in the plain area south of the Yangtze River in China, but rarely seen in the north of the Yangtze River. It is an important fishery resource in the middle and lower reaches of the Yangtze River and lakes along the Yangtze River, and is the main breeding object of lakes and ponds. It is one of the "four big fish" in freshwater culture in China.

In addition, it is commonly known as "black miscellaneous", "black miscellaneous" or "snail miscellaneous" in Anhui, and it is named because of its black body and snail-loving. The common "herring" in Northeast China is not herring, but should be written as "mackerel", which is a deep-sea fish. In China, the largest herring specimen weighing 2 18kg was caught in Jinniu Lake, Liuhe District, Nanjing in 2005. It is 1.86m long and weighs 2 18kg, and it is about forty years old by scale identification.

Black herring is also called black pomfret and snail green. Bony fish, CYPRINIDAE. The body is sub-cylindrical, and the length exceeds1m. Blue-black, fin gray-black. The head is wide and flat, and the mouth end position is unnecessary. Pharyngeal teeth are molars. Habitat in the middle and lower levels, the staple food snails, mussels, shrimp and aquatic insects. 4-5 years old, sexually mature, spawning in the upper reaches of rivers, and can be artificially propagated. The individual is large and grows rapidly, and the largest individual reaches 70kg. This meat tastes delicious. It is the main freshwater fish culture object in China. It is distributed in major water systems in China, mainly in the plain south of the Yangtze River. Fish gall is poisonous.

Grass carp? Grass carp is CYPRINIDAE, CYPRINIDAE, CYPRINIDAE? ? ? ? A genus of the family. The common names of grass carp are: pomfret, pomfret, pomfret, grass pomfret, pomfret, grass carp, grass root (northeast), coarse fingered fish (southern Shandong), sea pomfret (south), hybrid, black herring and so on. English name: Grass carp. Rivers and lakes inhabiting plain areas generally prefer to live in the middle and lower layers of water and coastal areas with more aquatic plants. Sexually active, swimming fast, often foraging in groups. It is a typical herbivorous fish. Grass carp eat larvae, algae, etc. In the juvenile stage, grass carp also eat some carnivorous foods, such as earthworms and dragonflies. Overwintering in the deep water of mainstream or lake. Parent fish have the habit of swimming against the current during the breeding season. It has been transplanted to many countries in Asia, Europe, America and Africa. Because of its rapid growth and wide sources of feed, it is one of the four largest freshwater fish in China.

Grass carp, Cyprinidae. The body is slender, sub-cylindrical, and the body length is more than1m. The body is bluish yellow. The head is wide and flat, and the mouth end position is unnecessary. Pharyngeal tooth comb. It lives in the middle and lower layers of water and feeds on aquatic plants. Mature at 3-4 years old, spawning in the upper reaches of rivers, which can be artificially propagated. It grows fast, and the largest individual is about 30kg. It is the main freshwater fish culture object in China. Distributed in major water systems in China, the meat is delicious and the fish gall is toxic.

Silver carp? Silver carp (pronounced liá n yú) (silver carp), also known as silver carp, silver carp, silver carp and silver carp, belongs to CYPRINIDAE and is one of the four famous fish alongside herring, grass carp and silver carp. It is a typical filter-feeding fish.

The figure is flat on the side, slightly tall, spindle-shaped, with blue-gray back and white sides and abdomen. The pectoral fin does not exceed the base of the ventral fin. Fins are gray. The head is bigger. Eye position is very low. The balance is fine. The central horny edge of the abdomen extends from below the pectoral fin to the anus. The shape is similar to that of bighead carp, and silver carp is impatient and good at jumping.

Silver carp is sweet in taste, flat in nature, non-toxic, tender in meat and rich in nutrition, and it is one of the excellent fish species suitable for breeding. It is one of the main freshwater cultured fish in China. Distributed in major water systems throughout the country. Silver carp is a large freshwater fish raised artificially, which grows fast, has few diseases and high yield, and is mostly mixed with grass carp and carp.

Big head? Aristichthys nobilis is also called silver carp, silver carp, Baotou fish, bighead carp, silver carp, silver carp and male fish. It is a freshwater fish. Known as the "underwater scavenger", it is one of the four major fish in China. It looks like a silver carp with a flat body. The head is big and wide, and the mouth is wide and slightly upturned. The eye position is relatively low. Bighead carp grows in freshwater lakes, rivers, reservoirs and ponds. Most of them are distributed in the upper and middle waters. This is a kind of fish unique to China. It is widely distributed in China. It is one of the main objects of pond culture and reservoir fishery, and has high economic value. It is edible and has the effects of improving IQ, enhancing memory, supplementing nutrition and delaying aging.