Why do fish ponds die in large numbers after rain?

Many farmers will contract fish ponds to raise fish and shrimp to make money, and water quality is very important for fish and shrimp. After the rain, especially the heavy rain, the water in the fish pond will be affected more or less, so the water in the fish pond is turbid after the rain. At this time, we should pay attention to the disinfection and water purification of fish ponds, otherwise the fish will easily die of hypoxia or bacterial infection.

Why did a large number of fish ponds die after the rain 1? During the rainstorm, the water temperature in the pond dropped sharply, the photosynthesis was weakened due to insufficient light, and the microorganisms in the pond changed dramatically. Fish in fish ponds are prone to stress reaction and physical decline, which will hinder the growth of fish and even die on a large scale.

2. After the heavy rain, the salinity in the pond decreased, and sulfur dioxide and nitrogen oxides in the air were brought into the water, producing sulfurous acid and nitrous acid, which caused damage to the respiratory organs and digestive tract mucosa of fish, causing cell hypoxia and decreased immunity.

3. If it rains continuously, the sunshine is weak, the photosynthesis of algae is weak, the dissolved oxygen in the pond is insufficient, the indexes such as nitrite and ammonia nitrogen are increased, and a large number of algae die and precipitate, which leads to the increase of harmful substances in the water and affects the growth of fish.

4. After the heavy rain, harmful bacteria proliferate in large numbers, causing bacterial infection in fish and making it easy to get sick. It can be disinfected with strong water purifying agent such as chlorine dioxide to prevent fish diseases such as pre-pickled skin and rotten tail.

Rainy days, especially heavy rain, will change the ph value of water. Because rainwater contains a lot of sulfuric acid, it will lead to the decrease of ph value of shrimp farm water. The water quality is acidic. Acidic water can cause a large number of biological acidosis in water, whether it is fish, shrimp or other organisms such as aquatic plants.

What about the fish pond after it rains? 1. Check the pond in time after it rains to see if the water quality has changed. You can measure the water temperature and PH value to see if there is a lot of sediment, whether floating objects such as leaves, branches and sundries block the passage or enter the fish pond, whether the water level soars and whether there is a risk of flooding the pond.

2. If there is a lot of silt and water in the fish pond, change the water in time, discharge the silt and water and increase the oxygen. When too much muddy water cannot be discharged in time, zeolite powder can also be sprayed to clarify the water quality. Dead branches, fallen leaves, sundries, etc. should be salvaged in time to avoid the bottom sinking and rotting in the future, resulting in poor quality of the bottom.

3. The sudden change of water temperature will cause fish stress, which will lead to the decline or illness of fish and shrimp. You can compare the changes of water temperature before and after rain. For example, if the water temperature drops by more than 3℃, the pressure-resistant products will be sprayed.

4, after the rain, should open the aerator in the middle of the night, until dawn. This is because during this period, phytoplankton not only does not produce oxygen, but consumes oxygen. Therefore, at this time, when the dissolved oxygen in the water is the lowest, it is necessary to increase oxygen in time. Aeration is actually water transfer, which is not contradictory.

5. Bacterial diseases occur frequently after rain, so it should be disinfected in time. Sprinkle 700 grams of bleaching powder per mu in the whole pond once a day for 3 consecutive days. Pay attention to open the aerator after spraying the medicine to prevent the fish from floating without oxygen.

6. Pay attention to the change of water color. If the transparency of the fish pond exceeds 40 cm, it needs topdressing. Inorganic fertilizer can be applied topdressing to make fertilizer and water take effect quickly, but the dosage should follow the principle of small amount and multiple times. Don't use too much at a time to avoid damaging the water quality again. After water supply and fertilization, the beneficial algae are supplemented with EM bacteria every 10 day.

Do you want to turn on the aerator in the rainy fish pond? It depends on the specific situation. Generally speaking, it opens the next morning on a cloudy day, in order to directly stir the water and increase oxygen. Due to the weak photosynthesis on cloudy days, the dissolved oxygen in the pool water is less, and the dissolved oxygen in the pool water may drop to close to the oxygen threshold of fish after being consumed at night, so it should be at 3 ~ 5 am, and the density time of fish should be advanced if water and fertilizer are used.

When it rains continuously or there is danger of floating head due to water, fertilizer and fish density, it must be opened in front of the fish floating head. You can see the wild miscellaneous fish and shrimp in the pond, and they will open when there are signs of floating head, usually around midnight. Because there is very little oxygen in the pool water at this time, if the floating head of the cultured fish is opened again, it will be too late to save the fish, which will easily cause the fish to die in the pool. The oxygen tolerance of wild mixed fish and shrimp is lower than that of cultured fish, which can be used as a reference for starting up. Don't open it during the day in rainy days. The photosynthesis is weak during the day in rainy days, and the dissolved oxygen in the surface pool water will not be supersaturated. At this time, it is impossible to achieve the purpose of increasing oxygen by turning on the machine.

Impact on aquatic animals before and after the rainstorm, before the rainstorm, the air pressure was low, the weather was sultry, and the dissolved oxygen in the pool dropped rapidly, which easily made the cultured animals in an uncomfortable state.

During the rainstorm, the water temperature drops sharply, the light is weakened, a large number of microorganisms die, algae and bacteria are easy to transform, and the micro-ecological structure of the pond changes dramatically, which makes the cultured animals prone to "stress" reaction.

After the heavy rain, the weather is sunny and hot, and cyanobacteria multiply in most ponds, coupled with the decay of dead microorganisms, resulting in poor water quality in ponds and lack of oxygen at the bottom of ponds, which makes cultured animals prone to illness.