Observe the swimming situation of fish in the fry pond, climb the edge, swim alone, and whether there are fried groups when eating. , are signs of fry disease. Fish fry with dark grass green body color and black body color cannot be used. It is suggested to choose fry with overall specifications, fast swimming speed and consistent body color.
2. Water quality management: Spraying quicklime regularly: Generally, spraying quicklime or bleaching powder 1PPM on every mu of water surface and 20kg of water depth per meter every half month. Planned water change: inject fresh water every 10 day, 20 ~ 30 cm each time, and change water according to the actual situation before mid-July, with the water change rate of 1/2. Start the aerator every day: from June to mid-August. Grass carp is easy to float because of lack of oxygen. This festival lasts for 2-3 hours at noon on sunny days, 3-4 hours in the morning on cloudy days and once in the middle of the night to prevent fish from floating.
Patrol the pond carefully: keep abreast of the activities and food intake of fish in the pond, master the changes of water quality, and prevent and treat diseases early. Clean up the sundries in the pond and remove the green fodder leaves left by grass carp.
3. Prevent fish diseases
Prevention is the key to fish diseases, which is also the key to intensive cultivation of grass carp. Therefore, in the whole breeding process, we should focus most of our energy on the prevention and treatment of fish diseases, strictly control the disinfection of each link, and regularly feed bait made of Chinese herbal medicines and immune enhancers for health care, mixing them 2-3 times a month for 2-3 days each time.
The main causes of grass carp diseases are water quality deterioration, aging, mildew of polluted feed, seasonal bacterial and parasitic outbreaks and so on. The most effective treatment for gill rot, erythroderma and enteritis of grass carp is oral administration plus external use, and injection can be used when the outbreak treatment is expected.