Crucian carp is a widely distributed and adaptable fish, which has strong adaptability to various ecological environments. No matter the water depth, running water or still water, clear water or turbid water, it can adapt to the environment of hypoxia, acid and alkali. Generally speaking, it prefers to inhabit shallow bends, lake branches and ponds with overgrown water plants and slow water flow. It is not picky about water temperature, food, water quality and spawning grounds, and can grow and breed in the harsh environment that other cultured fish can't stand. Carassius auratus is also a kind of wide-temperature fish. The water temperature is around 10℃, even around 32℃, so it can feed and digest food. It can survive for a long time under the condition of low oxygen content in water, and it can only survive for a long time under the condition of low oxygen content. It will only die when the oxygen content is as low as 0. 1 mg/L, and it can also grow and reproduce in strongly alkaline water (PH=9). Crucian carp is an omnivorous fish, and their recipes are extremely extensive and diverse. Its animal foods are mainly cladocera, copepods, bryozoa, rotifers, freshwater shellfish, clams, chironomid larvae and shrimps. Plant food is mainly plant debris, but also diatoms, filamentous algae and aquatic plants. In southern China, crucian carp can be eaten almost all year round; In the north, people stopped eating from 65438+February to March of the following year. And June-August is their most vigorous foraging period. The growth rate of crucian carp is slow, only 50 grams in that year, 100- 150 grams in the second year and more than 300 grams in the third year. The largest individual can reach 2.5 kilograms, and the common individual is generally around 250 grams. Generally, southern crucian carp began to mature at 1 winter age, while northern crucian carp generally reached sexual maturity at 2 winter age. The spawning period can be extended from March to August, and its natural spawning grounds are mostly in shallow lakes and bays with overgrown aquatic plants. When spawning, the water temperature is above 15- 16℃, and most of them swim against the current to spawn. The spawning grounds are selected in shallow water areas where there are many aquatic plants along lakes and rivers, and they can also lay eggs in still water environments such as ponds. Oviposition usually occurs at midnight or early morning. Eggs are produced in batches, and fertilized eggs are sticky and attached to aquatic plants for development. The sexual problem of crucian carp is quite complicated. There have been reports of hermaphroditism. Some people say that crucian carp has the ability of gynogenesis. In nature, there are more females than males, and the sex ratio is about 4: 1. Carassius auratus is produced in all kinds of waters except Qinghai-Tibet Plateau in China. Crucian carp is tender, delicious and has high nutritional value. Every100g of edible part contains protein13.0-19.5g, fat1-7.0g, carbohydrate 0.1-5.8g, mineral (ash) 0.9g and heat 62-/. All parts of the country like to eat crucian carp, which is regarded as the first-class food; Especially after the parturient eats crucian carp soup, it can increase milk. In natural waters, the output of crucian carp ranks first in the total output of freshwater fish. Because crucian carp has strong adaptability, can grow and reproduce in various water bodies, and 1 year-old fish matures immediately and the population recovers quickly, it has always been regarded as the object of breeding collocation. There are many varieties of crucian carp, and the common goldfish is the variety of common crucian carp after artificial screening and domestication. The whole crucian carp is sweet in taste and warm in nature, and has the effects of invigorating spleen and regulating stomach, stimulating appetite, eliminating edema, stopping vomiting and promoting lactation. Fish eggs can regulate qi. Whole fish can be used as medicine to treat measles, mumps, toothache, gingival swelling and pain, breast swelling and pain, primary breast cancer, lung pain, lung abscess, external hemorrhoid, spleen and stomach weakness, anorexia, edema, ascites swelling, nausea and vomiting, stomachache, postpartum hypogalactia, postpartum hypogalactia, etc. Its bile can cure carbuncle, innominate swelling and scabies.