2. The seedlings should be put into the box "early", before the arrival of spring flood, and make full use of the organic matter washed into the storage (lake) in the farmland, grass seed field and flooded area of reservoirs and lakes. Before the fry are transported, pull the net for 1 ~ 3 times, stop eating 1 day, and transport on an empty stomach, so that the package is thin and fast. Pay attention to the observation 2 ~ 3 days after putting it in the box, and fish out the dead and injured fish in time to make up the quantity.
3. Density, variety collocation and specifications of seedlings under the box. The density of fish in the box depends on the characteristics of water body and the level of feeding. When silver carp and bighead carp are cultured in eutrophic water, 200 ~ 300 summer fish can be raised per square meter. In the cage with bighead carp as the main component, 10% silver carp can be built, and the cage with silver carp as the main component can be matched with 10% bighead carp. In addition, each box can be equipped with 20 ~ 30 tilapia summer flowers, so that they can eat algae attached to the cage to prevent the net from being blocked. Artificial feeding mainly includes grass, bream, carp and tilapia, with 200 or 300 summer fish per square meter. The specifications of the seedlings in the box should be more than 6 cm.
4, cage management and matters needing attention. (1) After the summer flower fingerlings are put into the box, they should be washed with clear water every day for the first three days to keep the net clean. (2) Put the good fish in the box. The fish in the box must be healthy, disease-free and harmless. Soaking in 2% salt solution for 5 minutes can prevent viral and bacterial diseases. Grass carp species were immunized by injection or immersion with inactivated hemorrhagic disease vaccine. (3) The feed is palatable and reasonable. When feeding artificial feed, powder, crumbs, flour and compound feed should be mixed according to the size of fish species to make the feed palatable. Fish species have higher requirements on the content of protein in feed at seedling stage, with the crude protein content of grass carp feed not less than 25% and carp feed reaching 36-38%. When feeding, insist on eating less and eating more meals, feeding 4 ~ 6 times a day. Feed them every day except in special weather to avoid being hungry.