What are the key technical points for fattening fish, shrimp and crabs in autumn?

1. Rational water exchange and cultivating nutrient-rich water. Starting from May, use "medicated bait" and "medicated liquid" to prevent and control diseases and pests once every month or every 20 days. During the transition period from summer to autumn, pay even more attention to water quality regulation; prevent the pond water from "turning" or becoming "old", and maintain suitable transparency of nutrient-rich water. Keep the transparency of fish ponds at about 25 cm, shrimp ponds between 30 and 36 cm, and crab ponds at 35 to 40 cm. If the pond water transparency is less than the normal requirement for fish, shrimp and crabs, promptly use quicklime at 5 to 7.5 kg per mu to regulate water quality; if it is greater than what is needed for the growth of fish, shrimp and crabs, apply fertilizer as appropriate to enrich the water.

2. Rational feeding to promote fattening and weight gain. After the Start of Autumn, the quality of bait fed to fish, shrimp and crabs should be improved and the amount appropriately increased. The daily feeding for fish is 5 to 6 percent of the total fish weight; the daily feeding for shrimp is 7 to 8 percent of the total shrimp weight, and the fresh protein bait fed accounts for 60 percent of the feed ratio; the daily feeding for crabs is 10 percent of the total crab weight, and the protein bait fed accounts for 65 percent of the feed amount; the daily feeding for loach is about 6 percent of the total loach weight, and the protein bait fed accounts for 60 percent of the feed amount. For farmed fish, shrimp and crabs, the feeding amount in October and November decreases as the air temperature and water temperature gradually drop, with daily feeding amounts of 3 percent for fish, 4 percent for shrimp, 4 to 5 percent for crabs, and about 4 percent for loach.

3. Rational use of medication to prevent and control diseases and pests. After the Start of Autumn, use pollution-free drugs such as chlorine dioxide to splash the whole pond once every 20 days or so (if shrimp or crabs become sick, use 200 g per mu of pond, once a day, for 3 to 4 consecutive days as one treatment course); at the same time, add drugs such as "ecdysone", "calcium tablets" and "oxytetracycline" to the bait and mix them into the feed, once a month, with each dosage accounting for about 0.5 per thousand of the bait ratio. Also, insist on patrolling the pond every morning and evening to observe feeding conditions and decide the amount to feed the next day; at the same time, carry out the "two preventions" work of preventing theft, preventing escape and preventing predators.