Why are grass carp called wild species?

Hunzi is a common name for grass carp in some places. As one of the four largest fish in China, it belongs to herbivorous fish, and usually lives in the middle and lower layers of water, or in places where there are many aquatic plants near the shore. This kind of fish has a lively nature, swims fast and feeds in groups. It generally feeds on aquatic plants and algae, but it can also eat meat and feed insects and earthworms.