When the temperature is changeable in spring and summer, the breeding brocade carp should beware of parasitic diseases.

Spring is the season when everything recovers. When the water temperature reaches more than 10 ℃, koi begins to feed and enter the normal stage of growth and development. But at the same time, the weather changes fiercely from March to April every year, when spring turns to summer, and the temperature rises obviously. at the same time, due to the frequent occurrence of weather such as overcast plum and rain in this season, the precipitation increases obviously, the light is insufficient, and the air pressure is low. the temperature fluctuates greatly, often under the influence of cold wave and strong cold air, and the first cold and warm weather is more, which is easy to cause the stress reaction of pond cultured koi to be enhanced. Leading to a gradual increase in fish diseases. Especially in the Pearl River Delta region, the first peak of fish disease is coming in late March every year.

According to the reaction of some farmers in Lecong Town and Longjiang Town in Shunde, various parasitic diseases have occurred in koi in some farms since April this year, especially rotifer disease. On the other hand, the parasitism of koi will affect the appearance and reduce the ornamental value. Therefore, it is necessary to actively prevent and control, usually pay attention to adjust the water quality, and according to the specific situation to use more mature insecticidal drugs to kill. The following introduces the prevention and control methods of several common parasitic diseases of koi for reference. The main results are as follows: 1. The third generation of koi insect disease: the body surface of the diseased fish is either congested, or local mucus falls off and fades, and some Gill filaments fester. Microscopic examination showed that there were three generations of worms in the Gill of the fish. The traditional insecticide can effectively treat the disease. The mixture of potassium permanganate and crystal trichlorfon (17:3) was sprinkled in the whole pool and the dosage was 1~2ppm, which still had good effect at low temperature. 2. Koi finger ring disease: the ring worm is generally parasitic on the gills of the brocade carp, destroying the Gill tissue and causing anemia and weight loss of the fish. Gill filament mucus of diseased fish increased, swollen, all or part of it was pale, with decay; Gill cover opened, moved slowly, food intake decreased sharply, dyspnea, sensitivity to external stimulation decreased greatly, even lost response, floating on the shore, motionless or jumping sharply in the water. Prevention and treatment: (1) after the onset of the disease, wash the diseased fish with 20 mg / L potassium permanganate solution for 15 minutes. (2) Mebendazole was sprinkled in the whole pond at a dose of 15 grams per mu of water depth, and no new water was added within 72 hours after medication. (3) take enrofloxacin bait internally and mix the bait with 2 grams of enrofloxacin powder for every 100 kg of fish every day. (4) after the disease is under control, the sick fish pond should be injected with about 20 cm of fresh water. 3. Brocade carp rotifer: rotifer mainly destroys the Gill tissue of brocade carp, affects the respiration of fish and causes fish death. After the onset of the disease, the diseased fish scrubbed the bottom and retracted the fins. After being attacked by pathogens, koi likes to swim on the water surface or by the pool, like a "floating head", thin and weak, dull fish, dark body color, fish body loss of luster. Prevention and treatment methods: (1) Salt bath method: the diseased fish were treated with 1%-2% saline solution for about 10 minutes, once every other day, for 3 times in a row. Rest the sick fish in a special tank or pond and take good care of it. (2) potassium permanganate medicine bath method: every 5 kilograms of fish culture water is dissolved in 0.1 grams of potassium permanganate, medicine bath sick fish, bath 15 minutes for 25 minutes, once every other day, 3 times in a row. Rest the sick fish in a special tank or pond and take good care of it. (3) Trichlorfon solution medicine bath: 0.2ppm trichlorfon solution medicine bath sick fish for about 1 hour, once a day. The pesticide used in the fish pond should be arranged according to the fat and thin of the water body, the weather, the water temperature and the activity of the fish. Experienced farmers remind: when using drugs, we should pay attention to control the dosage, do not overuse drugs, otherwise it is easy to cause the death of koi. When the weather and water temperature are normal, the fish can be sprinkled at 3: 4 p.m. when killing insects, special attention should be paid to observing the performance of koi. If there are abnormal conditions such as crazy swimming, shaking, edge, floating head, etc., you should immediately change 50% of the water and increase oxygen, and then observe. It should be noted that antibiotics should be used immediately after the end of insecticidal treatment.