High-density forage fish breeding method and device

The invention discloses a high-density forage fish breeding method and device. The method comprises the steps as follows: water area selection: a fresh water pond of 10 mu or more is selected; building of a forage fish breeding device: the forage fish breeding device is a water tank built beside or on the pond, the area of the water tank accounts for 1-5% of the area of the pond, and equipment for oxygenating a water body is arranged in the water tank; construction of a purification water tank: the pond is sequentially divided into a sedimentation tank, an aeration tank and an ecological tank, water in the ecological tank is pumped to the head end of the water tank, tail water and excrement and residual feed at the tail end of the water tank naturally flow or are pumped into the sedimentation tank, the tail water subjected to natural sedimentation automatically flows into the aeration tank through an overflow dam, the tail water subjected to aeration and oxygenation automatically flows into the ecological tan