Preventive disease measures must be taken before fish storage and transport

As the saying goes: "Buy a chicken that can crow, buy a fish that can jump." Yet many @#@233@#@ households, after a year of hard work, run into trouble when the time comes to @#@136@#@ adult fish: the fish do not tolerate storage and transport, their whole bodies become congested, and some even die. At this point most farmers think there is a problem with the feed. Indeed, some feed manufacturers, in order to one-sidedly lower the feed conversion ratio and increase fish growth rate, add hormones or hormone-like drugs such as olaquindox to the feed, causing the above phenomena during fish storage and transport. But there are many factors that make fish intolerant of storage and transport, roughly divided into three types: the first is caused by olaquindox poisoning; the second is caused by gill disease; the third is caused by bacterial hemorrhagic disease. Below is a specific analysis of these three situations, along with corresponding countermeasures.

1. Olaquindox poisoning and countermeasures

This condition mainly shows as general or local congestion and redness of the fish body, most obvious on the cheeks, abdomen, fin rays and their bases; the gill filaments are bright red or deep red; mortality on the day of long-distance transport is very high. Corresponding countermeasures: since there is no effective drug treatment, the only option is to stop feeding feed containing olaquindox, appropriately control fish growth, and sell in batches.

2. Gill disease and countermeasures

The main symptoms are inflammation, swelling, proliferation and fusion of the epithelial cells at the ends of the gill lamellae, with the gill filaments becoming club-shaped. Microscopic examination sometimes reveals large numbers of myxosporean parasites. Mucus on the gills increases, and the gills swell and become inflamed. The fish lack vitality, and body surface mucus is reduced. After long-distance transport, some fish swim weakly at the water surface, showing symptoms of oxygen deficiency; mortality is relatively low on day 1 and higher on days 2 to 3. Blood streaks appear on the abdomen, along with loss of scales and fin rays. Corresponding countermeasures: carry out fish disease prevention and control 1 month before selling the fish. ① Splash 90% crystalline trichlorfon over the whole pond at 0.5 g/cubic meter, once a day for 3 consecutive days. ② Splash chlorine dioxide over the whole pond, once a day for 2 to 3 consecutive times. ③ Medicated feed: mix 50 g of furazolidone into every 50 kg of feed and feed for 3 consecutive days.

3. Bacterial hemorrhagic disease and countermeasures

The main symptoms are congestion and hemorrhage of the body surface and various organs and tissues, protruding eyeballs, red and swollen anus, distended abdomen, and congestion and redness of the upper and lower jaws, oral cavity, operculum, abdomen and fin bases. Dissection reveals pale yellow or red ascites in the abdominal cavity, enlarged liver and kidneys, severe anemia, congested intestinal walls, and pinpoint hemorrhages on the mesentery. Dead fish can be seen even before transport, and mortality during transport is relatively high. Corresponding countermeasures: carry out fish disease prevention and control 1 month before selling the fish. ① Splash chlorine dioxide over the whole pond, once a day for 3 consecutive days. ② Medicated feed: add 50 g of furazolidone and 750 g of rhubarb (decocted into juice) to every 50 kg of feed, mix with the feed and feed for 3 to 6 days.