Key points of prevention and treatment of fish disease in early spring due to lack of water temperature change

Although it has entered the spring, the temperature is still low. When the water temperature is 5 ℃-14 ℃, most fish secrete less neurohormones, low digestive enzyme activity, fish do not like activity and feeding, and lack of biological feed; at the same time, the rapid rise and fall of water temperature will not only have a great impact on the growth and development of fish, but also lead to fish diseases and even death. Therefore, the key to aquaculture in spring is to prevent and control fish diseases, mainly to prevent the following diseases:

Prevention and treatment of fish disease in early spring

One is anorexia of pond fish. When the water temperature is lower than 15 ℃, most of the food intake decreases and the growth slows down; when the water temperature drops to 15 ℃, silver carp, bighead carp, grass carp and other fish are not fed concentrate feed, but only green feed is added; when the water temperature is 10 ℃, little or no green feed is added, but appropriate amount of feces can still be applied, but not more to prevent the water quality from getting worse.

Second, the pond water turns black. The low temperature and rain in spring and the hot and cold weather will cause the death of a large number of algae in the fish ponds, the water quality will deteriorate and the water color will turn black. in serious cases, the pond water will stink, resulting in anoxia and floating heads of fish in the ponds. In case of deterioration of water quality caused by continuous low temperature, overcast and rain, the water must be changed in time (15cm-30cm) to improve the water quality. In addition, quicklime (7-10 kg per mu) should be applied to sterilize and disinfect, agglomerate suspended solids and neutralize acidic water bodies, so as to reduce the harm to fish.

Third, the pond water is clear and transparent. There are often rainy days at the end of spring, and some ponds change from bluish brown to clear and transparent. Mainly due to excessive fertilizer water quality, too many zooplankton, followed by a small number of bighead carp. Because bighead carp feed on zooplankton and zooplankton feed on phytoplankton, when a large number of zooplankton eat phytoplankton, the pond water becomes clear, which is disadvantageous to the growth and development of pond fish. At this time, we should timely inject new water and increase dissolved oxygen in the water, keep 1 meter of pond water per mu, sprinkle with 2-2-3 crystal trichlorfon boiled water to kill zooplankton, appropriately increase the stocking density of bighead carp, and properly apply organic fertilizer to promote the reproduction of phytoplankton.

Fourth, diseases and insect pests in fish ponds. On continuous rainy days, some "old water" fish ponds, bighead carp and silver carp are prone to anchor head flea disease. if they are seriously infected, the fish will be dressed in a coir coat, which is disadvantageous to the growth and development of fish. Prevention and control measures: 350 kg-400 kg of pig and cow manure per mu, or 100 kg-150 kg of urea in human manure per mu, 1 meter of water depth per mu, 100 kg of wine trough, and sprinkle with 100-150 g chemical water of crystal trichlorfon, once a day, 2 ~ 3 times in a row.