The freshwater ornamental fishes in temperate zone mainly include red crucian carp, China goldfish and japanese koi, mainly from China and Japanese. The appearance of red crucian carp is similar to that of edible crucian carp, and it can be divided into red crucian carp, red and white crucian carp and five-flowered crucian carp according to different body colors. They are mainly kept in the fountains of lakes or tourist attractions, such as "Jiuqu Bridge" in Shanghai Old Town God Temple and "Huagang Fish Watching" in Hangzhou. Fancy fish

The ancestor of China goldfish is the wild red crucian carp hundreds of years ago, which was first seen in the releasing pond in Jiaxing, Zhejiang Province in the early Northern Song Dynasty. 1 163, Emperor Zhao Gou of the Southern Song Dynasty raised a large number of golden crucian carp in the palace. Family-raised goldfish spread from the palace to the people and gradually spread. The domestication of goldfish has gone through two stages: pond culture and pot culture. After careful selection by several generations of folk artists, the single-tailed goldfish gradually developed into two-tailed, three-tailed and four-tailed goldfish, and the color gradually changed from a single red to red and white, five flowers, black, blue and purple. Its shape has also changed from a long and narrow spindle to an oval and spherical shape, and its variety has changed from a single golden crucian carp to today's rich and colorful. According to historical records, China goldfish was first introduced to Japan in the Ming Dynasty, and it was introduced to Japan again in 16 15- 1623. ? Japanese koi's original species is red carp, which was introduced to Japan from China in the early days. After careful cultivation by the Japanese people, it has gradually become one of the world-famous ornamental fish. The main varieties in japanese koi are red and white, Showa tricolor, Dazheng tricolor and Qiu Cui.