The cause of death of grass carp fry

The low survival rate of fish fry has always been a common problem. Fish farmers have basically encountered the phenomenon of fry death. As one of the common fish species, grass carp are more likely to encounter such problems. The death of grass carp fry is caused by both natural and artificial factors, and the latter is more likely to have this problem. Let's understand the causes of frequent death of grass carp fry.

1. Improper transportation

The technical requirements for self-cultivation of fish fry are not generally high, so they are generally purchased directly for fish fry culture, and the fish fry purchased are prone to problems during transportation. Some fish fry in the transportation due to improper operation, resulting in maladaptation, stress reaction death, while others due to a better system, survive longer, wait until the breeding pond will begin to die, if the purchase of grass carp fry died in bulk in just a few days, then it is probably this reason. In such a situation, do not rush to put the fry into the nursery pond, give it some time to adapt, and then adjust the environment of the nursery pond to the most suitable level for grass carp fry survival, so that death will be much less.

2. Drug stimulation

In the early days, grass carp fry have no resistance to diseases and insects, and farmers do not want them to encounter diseases and insects, so they will choose to use pesticides to kill insects. Even these agents will actually give greater stimulation to grass carp seedlings, causing a large number of deaths. These agents can also do harm to grass carp fry. If the concentration is a little lower, they can still carry it, but if the concentration is high when the medicine is used, or when it is relatively dense, it will not only kill insects, but also affect grass carp fry. When using grass carp fry, we must pay attention to whether it is suitable or not. Many people kill insects and finally solve the problem with fish fry. This is a very error-prone link.

3. Hypoxia

The death of fish fry caused by hypoxia is very normal, the general threat is not very great, because this sign is more obvious, farmers have time to adjust. Due to the long culture time and inadequate cleaning in the ponds, there will naturally be a lack of oxygen in the ponds. Grass carp fry themselves like waters with higher oxygen concentrations, but they do not have such a strong respiratory system as adult fish. A little lower oxygen concentration will lead to dead seedlings. If the floating head of fish fry is frequent, it is best to prepare for aeration in advance.

4. Disease

As far as the disease is concerned, this is a relatively big threat, the disease for the spread of adult fish infection, but also let everyone have time to treat, but for fish fry, there is little time for everyone to react to treatment. Especially at this stage in summer, grass carp fry have the best chance of getting sick, such as enteritis and rotten gills, which may appear on fish fry. In addition, the invasion of various germs and parasites caused by the deterioration of water quality also need to be guarded against.

Although grass carp itself is relatively easy to feed, it is easy to have problems in its fry period, which is also the reason why it is very simple for larger grass carp to be fed. It may be almost gone at the fry stage.