Introduction to the four major fishes: Herring, grass carp, silver carp, and bighead carp are all unique to China. They have the characteristics of large size, wide range of food habits, rapid growth, high reproduction rate, and strong adaptability. These characteristics can help them become a Qualified "pioneers", inhabiting a variety of water environments. Herring has a throat tooth similar to a "crusher", which can easily crush shelled molluscs such as snails and young clams; grass carp can destroy a large number of aquatic plants; silver carp and bighead carp filter out plankton for food, so they can Effectively control the number of blue algae and maintain the balance of aquatic ecology.