Rainbow trout is native to the Arctic Ocean in North America, Alaska and California in the United States, and also exists in mountains and streams in Japan. It is said that a Japanese woodcutter saw the graceful posture of this fish and wanted to take it home to raise and watch it. Unexpectedly, the fish was so delicate that it died before it got home. So I stewed the wine and found that the meat was particularly tender, delicious and very delicious. Later, more and more people knew about it.

Japanese aquatic experts have proved that this kind of fish contains a lot of DHA and EPA, which are essential substances for human brain nutrition and have a good effect on cardiovascular diseases. At the same time, it is extremely rich in nutrition and is a treasure of nourishing nutrition. Domesticated rainbow trout has been highly valued by the Japanese government, and it has the same name as the national flower "Sakura" and is called "Sakura Trout". Later, other countries followed Japan's example, and New Zealand called this kind of fish "sacred fish" and made laws to protect it. Become a high-end gift between heads of state.

1959 When Premier Zhou Enlai visited North Korea, Kim Il Sung presented it to Premier Zhou as a "national gift". Premier Zhou brought rainbow trout back to China and gave it to Chairman Mao, who praised the fish.

Salmon (Salmo airdneri) is a genus of Salmoniformes and Salmonidae. Also known as salmon. Native to the mountains and streams of Alaska, USA. From 65438 to 0866, it was transplanted to the eastern United States, Japan, Europe, Oceania, South America and East Asia for reproduction and proliferation. It has become the most widely cultivated precious fish in the world. 1May, 985, rainbow trout was introduced from Maqu Farm in Gansu for the first time, and it was successfully cultured in Hada Muquan, Haiyan County, Qinghai Province.

Rainbow trout has a long body, a kissing garden and small scales. The back of the head and the top of the head are cyan, blue-green, yellow-green or brown. The side is silvery white, white, light yellow green or gray. The abdomen is silvery white, white or grayish white. There is a wide and bright purple rainbow band along the lateral line, which extends to the base of the fish tail fin, hence the name. Half or all the edges are covered with small black spots. There is a fat fin.

The limit temperature of rainbow trout is 0-30℃, the suitable living temperature is 12- 18℃, and the optimum growth temperature is 16- 18℃. When the temperature is lower than 7℃ or higher than 20℃, the appetite decreases, the growth slows down, when it exceeds 24℃, it stops eating, and then gradually weakens and dies. It needs high dissolved oxygen in water. When the dissolved oxygen is lower than 3 mg/L and lower than 4.3 mg/L, "floating head" appears and death begins. When the dissolved oxygen is less than 5 mg/L, the respiration rate is accelerated. In order to keep rainbow trout in a good growth state, dissolved oxygen should be above 6 mg/L and above 9 mg/L to grow rapidly.

Rainbow trout likes to be stimulated by countercurrent water, which causes normal exercise and accelerates material metabolism in the body. Therefore, rainbow trout has been cultured in flowing water with a flow rate of 20-30 cm/s, and their feeding habits are mainly terrestrial and aquatic insects, crustaceans, shellfish and small fish, and they also eat leaves and seeds of aquatic plants. Annual feeding, even during spawning. In the case of artificial feeding, compound feed can be eaten well. It grows faster in a good environment, and its life span is usually 8- 1 1 year, the largest individual can reach 9 kg, and the largest individual found in natural water is 25 kg.

Male fish reach maturity in 2 years, and female fish reach maturity in 3 years. The spawning water temperature is 4-65438 03℃, and the optimum water temperature is 8-65438 02℃. In the natural environment, the spawning ground is in the gravel river or tributary, and the female fish digs the spawning pit to protect the male fish and ensure egg precipitation. There are usually 800- 1000 fertilized eggs in each spawning pit, and the number of eggs conceived by an individual is 10000- 13000, which is produced several times. It is known that the same individual has propagated five times. The identification of male and female fish is mainly based on the head. The male fish is the one with a big mouth and a big nose, and the female fish is the one with a blunt nose and mouth.

Rainbow trout grows and reproduces quickly: the growth of rainbow trout varies greatly due to water temperature, environmental conditions and food intake. At 16℃, it usually grows to 100 ~ 200g in one year, 400 ~ 1000g in two years, 0/000 ~ 2000g in three years and 40 ~ 50g in one year and two years at 9℃. Under the condition of artificial feeding, the maximum individual reached 7. Five kilos. Usually, the age of sexual maturity of male individuals is 1~5 years old, mostly 3~4 years old, and that of female individuals is 4~5 years old when they are 2~6 years old. Mature individuals is generally around 15~40 cm. Rainbow trout is a cold-water fish with strong adaptability in salmon. China is rich in cold water resources suitable for rainbow trout culture, and the development of rainbow trout culture has broad prospects.

Rainbow trout is a valuable aquatic product, with plump meat, tender meat, few thorns, delicious taste, protein, high fat content and rich brain-nourishing substances (20c5aenoic acid). Easy to process, it is the best-selling precious fish food in the international market.