Fish feed and preparation method thereof

The invention discloses a fish feed. The fish feed comprises the following components in parts by weight: 55 to 65 parts of mushroom residue, 15 to 25 parts of cake-shaped rape seed dregs, 15 to 25 parts of corn and 1 to 3 parts of a Chinese herbal medicine additive. The Chinese herbal medicine additive comprises fennel, dandelion and lucerne meal, the content of fennel is 20wt% to 30wt%, the content of dandelion is 45wt% to 60wt%, and the content of lucerne meal is 20wt% to 30wt%. The preparation method of the fish feed comprises the following steps: A, taking white mushroom residue of mycelium, after smashing, adding 30 to 36 parts of water and 0.6 to 0.8 part of a combination fungicide; B, piling a product obtained in the step A on the ground, carrying out anaerobic fermentation for 6 to 8 days, overturning once, then adding 10 to 16 parts of water, and carrying out anaerobic fermentation for 5 to 7 days again; C, loading a product obtained in the step B in a plurality of plastic bags in batches, sealing f