Grass carp fry should be sold and cultured in the pond after the swim bladder is inflated and can swim horizontally, but the fry age should not be too long, otherwise the survival rate will be reduced. Qualified fry should be transparent, bright and not black; Swimming in groups, lively action, such as slightly stirring the water in the container, fry should swim against the current; The deformity rate and injury rate of fry should be less than 3%; The specifications are neat and the individual is large. Qualified grass carp fingerlings should have intact fins and scales, smooth and sticky body surface, normal color, lively swimming, deformity rate and injury rate less than 1%, no infectious diseases and no parasitic infection. The specifications of fish species should reach the average specifications of local fry, and the fish body should be strong and the fatness should be moderate.