Raising fry with grass pulp: fast growth and high survival rate

Fish pond

    Grass is rich in comprehensive nutrients and high in crude protein. When grass is ground into pulp to raise fry, the nutrient utilization rate is high, and the leftover pulp decomposes to fertilize the water, promoting the growth of plankton and providing abundant natural food for the fry. Therefore, fry raised with grass pulp grow fast and have a high survival rate. The key technical points are as follows.

    I. Pulping

    Use a high-speed pulper to grind water hyacinth, water lettuce, alligator weed and some terrestrial grasses (must be tender grass) into pulp. Before pulping, all grasses must be rinsed clean with fresh water and soaked in bleaching powder solution for disinfection. When pulping, feed the material in small amounts several times, master the ratio of grass to water well, and grind the pulp as fine as possible to increase the suspension time of the pulp particles in the water and improve the utilization rate. After pulping, add salt at 0.3%-0.5% of the grass weight and mix well (to serve a disinfecting function), let it stand for 3 or 4 hours, then splash it over the whole pond.

    II. Feeding

    1. Quantity. Generally, splash 50 kg-75 kg of pulp per mu of water surface per day. The feeding amount should be increased or decreased as appropriate according to the growth of the fish, weather and changes in water quality. Three days before stocking the fry, splash about 130 kg per mu as a base fertilizer to ensure the pond has fertilized water as soon as the fry are released. In ponds mixed with non-herbivorous fish, some concentrated feed should be appropriately added to the grass pulp.

    2. Time. Generally splash over the whole pond twice, at around 8 a.m. and around 4 p.m. If splashed too early, dissolved oxygen is low, activity is poor and the fish eat little; if splashed too late, the fry cannot finish it, and the pulp decomposes in the water, easily damaging water quality. If the fry are abnormal or the weather is muggy and rain is coming, be sure to splash less or not at all.

    III. Management

    After feeding grass pulp, promptly and in stages add fresh water to the pond to raise the water level, increase the fry's activity space, improve water quality and raise dissolved oxygen; appropriately splashing quicklime water not only has a disinfecting effect but also neutralizes the acidic substances from the decomposition of the grass pulp, making the water pH more suitable, thereby promoting the reproduction of beneficial plankton and the growth of the fry.