Prevention and Treatment of Hemorrhagic Disease in Crucian Carp Farming

June to September is the peak period for fish disease onset. In adult fish ponds, hemorrhagic fulminant fish disease in crucian carp often occurs, and it endangers silver carp, bighead carp, and blunt snout bream, bringing heavy losses to farmers. General conventional medication treatment is not very effective. After years of repeated observation and treatment, researchers have explored some new methods and experiences, introduced below for reference. (1) For every 100 kg of fish, use medicated bait made with 20 g furazolidone or oxytetracycline, feeding continuously for 3 days as one treatment course. (2) Dissolve 0.5 ppm strong chlorine in water and splash it over the whole pond. (3) Use combined treatment: On the 1st day, splash 0.5 g of Yuchlorin per cubic meter of water over the whole pond, and stop feeding for 1 day; from the 2nd day onward, use 8 g Yuchlorin, 4 g human-use furazolidone, 5 g oxytetracycline, and 100 g table salt per kg of concentrated feed, crush and mix them, add water and mix well, then feed once a day for 3 consecutive days. (4) Use comprehensive treatment: For every 667 sq m of water surface with a water depth of 1 m, use 2 kg tobacco leaves, 14 ml Decis, 333 g copper sulfate, and 270 g dried Isatis root. Method: First place the tobacco leaves in a large iron pot and boil them; after 2 hours, splash the liquid over the whole pond. Then pour Decis into a wooden basin, dilute with water, and splash it over the whole pond. On the morning of the 2nd day, first decoct Isatis root in water, pour it into a wooden basin, dilute with water, and splash it over the whole pond. Then dilute the copper sulfate and splash it over the whole pond. After 3 to 4 days, the diseased fish recover.

Precautions: (1) The above treatments are for reference only, and efficacy should be verified before formal promotion. If a large number of fish become diseased before verification, technicians should be asked to handle it. (2) If the fish have parasites, the parasites must first be killed with medication, and then treatment should be carried out according to the above methods. (3) After medication, do not immediately pull the net or drain the water, so as to avoid injuring the fish and accelerating infection.