How to improve the survival rate of fry after they are stocked in the pond

The period from when the fry are purchased to when they are put into the pond is the most prone to problems, because transport makes the fry relatively weak, and when they are stocked, the change of environment may make them unable to adapt. Some fish farmers have suffered quite a few losses in this regard, so much so that every time they buy fry they have to buy a lot more to ensure the number they want to raise. So how can the survival rate of fry after stocking be improved?

1. Pond disinfection

In the early stage, the fry are poor in every respect, and the ways to artificially improve their constitution are limited, so what we can do is create a good living environment for the fry to compensate and improve their survival rate. Disinfection is essential. At present, quicklime is generally used to disinfect the pond; every corner must be evenly sprinkled, and after soaking for a period of time the water is drained out, then rinsed a second time, and then left idle for about a week. When disinfecting the pond, the silt at the bottom and some of the larger debris around it must be cleared away.

2. Control the water temperature

Water temperature has a very important effect on fry; if the temperature is too high or too low it will cause problems with the fry on a large scale. Generally, the water temperature for stocking fry in the pond only needs to be around 20-22°C, and before they are put in, the water temperature of the rearing pond and the water temperature of the pond should preferably be fairly close, with the difference between them generally not exceeding 2°C. That is to say, if the water temperature before stocking is 21°C, then the pond water temperature should preferably be around 19-23°C, otherwise stress reactions easily occur, meaning the fry cannot adapt to the temperature and die.

3. Disease prevention

After the fry are stocked, parasite prevention and the occurrence of gas bubble disease must be handled well; these are the two situations most easily encountered after stocking. Parasites include trichodina, dactylogyrus and so on, which can be treated with the corresponding medicines; generally, when disinfection is done thoroughly, the chance of them appearing is much smaller. As for gas bubble disease, there are many triggering factors; for example, when there is more dissolved oxygen in the water, the incidence of gas bubble disease in fry increases, and when elements such as ammonia nitrogen are on the high side, gas bubble disease may also be triggered at the tail. Drugs such as Jiang'anling have a certain preventive effect on this.

4. Cultivate the water and divide the pond

Before the fry are put into the water, the water must first be tested to see whether the current water quality is suitable for rearing, and only after it is confirmed to be all right should all of them be stocked in the pond. At this time the fry can rely on the plankton and such in the water to survive, so before stocking it is best to cultivate the water first, so that there are more microorganisms in the water and the fry have better food. Secondly, after stocking it is not a matter of immediately releasing the fry into the whole pond, as that will kill many fry. Generally, after stocking they need to live in a cage for a period of time; one reason is to let them adapt to pond life later on, and the other is to fatten them up, and then they are divided among ponds. Larger fry still have a stronger ability to survive, and generally when they are about 3-5 cm they can be divided among ponds.

The later steps actually revolve around these as well, so when the fry's living environment and other aspects are all relatively good, their survival rate naturally rises. If you want to learn more related information, you can follow us.