家鱼的活动水层不同,食性也不一样,实行混养可使水体和各种饵料得到充分利用。例如:鲢,鳙鱼喜在上层活动,草鱼多在中层活动,鲤、鲫鱼多在底层觅食,混养可以各得其所。在食性方面,鲢鱼主要吃浮游植物,鳙鱼食浮游动物,青鱼食螺、蚬。草、鳊、鲂鱼吃草;鲤、鲫鱼在地底取食底栖生物和残渣剩饵。由于他们的食 The activities of fish in different water levels, food is not the same, the implementation of polyculture can make full use of water and a variety of food. For example: silver carp, bighead carp hi in the upper activities, grass carp in the middle activities, carp, crucian carp and more in the bottom of feeding, polyculture can be their own place. In terms of diet, the silver carp mainly eat phytoplankton, mackerel zooplankton, Ipomoea, 蚬. Grass, pomfret, bonito grazing; carp, carp feeding in the ground benthic organisms and residual bait. Because of their food