Prevention and control of bubble disease of cultured overwintering carp

June to September is the peak season of fish disease. Crucian carp hemorrhagic outbreak disease often occurs in adult fish ponds, and endangers silver carp, bighead carp and amblycephala, bringing heavy losses to farmers. General conventional drug treatment effect is not good, after many years of repeated observation and treatment, researchers explore some new methods and experience as follows, for reference. (1)Each 100 kg fish with 20 grams of furazolidone or oxytetracycline made of bait, continuous feeding for 3 days as a course of treatment. (2)0.5ppm strong chlorine was poured into the whole pool. (3)Mixed treatment: on the first day, 0.5g of euchlorjing was sprinkled in the whole pool per cubic meter of water, and food was stopped for 1 day; on the second day, 8g of euchlorjing, 4g of furazolidone for human use, 5g of oxytetracycline and 100g of salt were used per kilogram of concentrated feed, smashed and mixed with water, and fed once a day for 3 days. (4)Comprehensive treatment was adopted: 2 kg of tobacco leaves, 14 ml of dimefon, 333 g of copper sulfate and 270 g of isatis root (dry) were used for every 667 square meters of water surface and 1 meter of water depth. Usage: Put the tobacco leaves in a large iron pan and boil them. After 2 hours, sprinkle them all over the pool. Then pour the enemy into the wooden basin, dilute with water, and sprinkle the whole pool. On the morning of the second day, the isatis root is first poured into a wooden basin and diluted with water, and the whole pool is sprinkled. Then dilute the copper sulfate and sprinkle the whole pool. After 3 - 4 days, the fish recovered.

Notes: (1) The above treatments are for reference only, and the efficacy should be verified before formal promotion. If a large number of fish are infected before verification, technicians should be invited to handle them. (2)If fish have parasites, they must first be killed with drugs and then treated as described above. (3)After medication, do not immediately pull the net or buckle water, so as not to hurt the fish and accelerate infection.

In late January 2004, bubble disease occurred in a winter pond of adult carp in Baodi, Tianjin. The basic information is as follows:

The fish pond is about 10 mu. The water source is ditch water. Carp is mainly raised. Carp and grass carp are sick and dead. The average weight of carp is 1.5 kg/tail. The average weight of grass carp is 1 kg/tail. The pond water has been frozen, but some places are not frozen because sick fish swim back and forth. Some fish body surface between the fins, tail fin base, snout under the epidermis filled with bubbles. There are red bleeds on the dead fish, and the average number of dead fish is 5 - 6 per day. Ammonia nitrogen and hydrogen sulfide test results are normal, only dissolved oxygen seriously exceeded, diagnosed as bubble disease.

Bubble disease occurs due to high dissolved gases (such as oxygen, nitrogen, hydrogen sulfide) in water, but mainly due to high oxygen content in water. In this case, a large amount of ditch water was injected into the pond before overwintering. The water quality was relatively rich, and there were many organic substances in the water. Planktonic algae multiplied in large quantities, which caused the oxygen content in the water to be too high and caused disease. After winter, the pond water freezes, and the fish activity is not easy to observe. After the fish is found to be sick, the fish farmers sprinkle salt (7 g/m3) for 3 days continuously, but the effect is not good because of the serious illness. Then the method of sprinkling copper sulfate in the whole pool was adopted. 0.7 g was used per cubic meter of water, and the fish and shrimp music was sprinkled every 2~3 hours. 0.3~0.4 g was used per cubic meter of water, and the interval was two days. After three days, the disease was sprinkled once again. In general, people only pay attention to increasing dissolved oxygen in the pool, but ignore the harm of excessive dissolved oxygen. Although adult fish suffer from bubble disease less likely, mortality is not high, but if the disease is serious, will also cause some losses, so can not be taken lightly.