What are the four key points to get right for fish farming at the start of spring?

1. Fertilization: In early spring, when the pond water temperature stabilizes at 8°C-10°C, start applying supplemental fertilizer to cultivate natural food organisms in the water. The amount of fertilizer should be determined according to the fertility of the water quality and the quality of the fertilizer. Generally, apply 60-90 kg of human excrement and urine per mu; or 100-150 kg of livestock manure. If chemical fertilizer is used, follow a nitrogen-to-phosphorus-to-potassium ratio of 1:1:0.5. When applying, first crush and mix with water, then splash evenly over the whole pond, with a total amount of 3-7 kg per mu, and an interval of 5-10 days between each application. It is best to keep the pond water quality yellow-brown or yellow-green, with a transparency of about 30 cm.

2. Feeding: When the water temperature reaches 10°C, fish begin to move, feed and grow. In early spring, feeding should focus on concentrated feeds such as soybean cake, wheat bran and cornmeal, once a day at a fixed place and time, with each feeding amount at 1.5%-3% of the fish body weight. Later, as the water temperature rises, gradually increase the feeding amount and change to feeding twice a day. At the same time, for ponds mainly raising grass carp, feed an appropriate amount of aquatic and terrestrial grasses; the best amount is what can be eaten within 4-6 hours after feeding. The specific feeding amount should also be flexibly controlled according to water temperature, weather and the feeding conditions of the fish.

3. Water addition: In early spring, because the water temperature is low, the fish are small, and their activity and food intake are low, the pond water should not be too deep. As the water temperature rises and the fish grow larger, gradually deepen the water level. In early spring, it is best to do one major water change, replacing 1/2 of the entire pond volume. After that, add water once every 15 days, raising the water level by 10-15 cm each time. In March and April, keep the pond water level at about 1 m. At the same time, prevent sewage and harmful organisms from flowing in.

4. Disease prevention: The pond should have dedicated management, and persist in patrolling the pond every morning and evening to check the fertility of the water quality and determine the amount of fertilizer and feed. Promptly remove leftover bait, keep the pond water clean, and prohibit feeding spoiled feed. Regularly use drugs to prevent fish diseases. Every 15 days, alternately splash the whole pond once with 1 ppm bleaching powder and 0.7 ppm copper sulfate aqueous solution. If fish are found to be sick, diagnose and treat them promptly.