Novel net cage culture device

A novel net cage culture device relates to the technical field of fish culture. A buoyant device consists of a wooden plate, a gasoline can and steel tubes, wherein the steel tubes are arranged on the gasoline can, the wooden plate is laid on the steel tubes, a large net cage and small net cages are arranged in the buoyant device, a plurality of small net cages are arranged in the large net cage, and pedants are arranged on the four corners of the bottoms of both the large net cage and the small net cages. The small net cages are special culture net cages and used for culturing feeding fishes such as tilapia generally, the large net cage is additionally hung on the peripheries of the small net cages, filter feeding fishes such as chub and aristichthys nobilis can be cultured in the gaps among the large and small net cages and are used for eating (eliminating) the excrement, residue feed and feed which is leaked from the nets of the special culture fishes, so that a purification function is realized, culture c