Introduction to the rainbow trout breeding base: Rainbow trout is a cold-water fish that originally grew in the cool springs of mountain streams on the west coast of California, USA. Later it spread to Japan. When Premier Zhou visited Japan, a friend sent him to Beijing. After a long period of localized breeding and training, aquaculture experts finally found the cool and sweet spring water of Huairou Xiangshui Lake for breeding and hatching. Xiangshui Lake can be said to be the first home of rainbow trout in China.