Eight precautions to prevent accidental loss of fish fry into the pond

Fish fry enter the pond

Every year the Spring Equinox is the latest time to release fish fry. The fish fry just purchased are frail. If they are not careful when they enter the pond, they may cause great losses or even be wiped out. Therefore, the author particularly reminds farmers to pay attention to the following eight points when fry enter the pond:

1. The fish fry should be pulled out of the empty pond several times with a close eye net the day before entering the pond.

On the one hand, the remaining pond cleaning drugs accumulated at the bottom of the pond can be fully dissolved to prevent the poisoning of fish fry; on the other hand, the enemy can be further eliminated, and if the enemy is found, the whole pool can be sprinkled with 0.5 g / m3 of trichlorfon, this concentration has no killing effect on rotifers.

2. Before entering the pond, the fish fry must check whether the drug virulence of the clearing pond has disappeared, and whether the fertility of the water is appropriate.

First of all, take half a bucket of water, because sometimes the virulence of the surface water has disappeared, but the virulence of the bottom layer is still very strong. Put the fry in the water for 8-10 hours to see if it is normal to determine whether the fry can enter the pond. The pH value should be in the range of 7-8.5. Secondly, the fertility of the water can be judged according to the water color, transparency and the biological conditions of the bait. If the pond water is found to be overfertilized, it can be adjusted by adding clear water. If the fertility of the pool water is not enough, a small amount of chemical fertilizer or artificial bait should be added immediately.

3. When the fish fry enter the pond, the water temperature should not be lower than the water temperature of 3 ℃. If the water temperature difference is too large, the temperature difference should be adjusted gradually, and the fish fry should adapt before entering the pond.

For fish fry transported in plastic bags, the opening of the plastic bag should be slowly placed in advance before entering the pond, and then the fish fry should be slowly poured into the box 10-20 minutes later, so as to adjust the water temperature difference and the adaptation of fish fry to the change of air pressure in the bag. Some people call it "slow fry". If the fry is found to be lying on its back when opening the bag, it is a phenomenon of carbon dioxide poisoning, as long as the fry is slow and put in clear water for a period of time. If the fry is dumped directly from the bag into the pond, even if the naked eye observes that life is normal during stocking, death will occur after entering the pond, that is, death after transportation. Therefore, when transporting fish fry in plastic bags, it is necessary to operate carefully when entering the pond, and slow-down treatment is an essential and important step.

4. Fish fry should be disinfected with drugs before entering the pond.

Fish fry can be soaked in 1% baking soda for 20-30 minutes or 10 IU/L penicillin solution for 1 hour before entering the pond.

5. stick to the fish fry and go down to the pond after eating.

The production practice of fish fry feeding has proved that if the fish fry are fed with cooked egg yolk or feed yeast for 1 or 2 times before entering the pond, the survival rate and growth rate are significantly higher than those without rotifer feeding, so many places insist that the fish fry go into the pond after they are full.

After the fish fry arrived, the fish fry were first fed in a cage, and then re-counted into the pool. When the fry is collected in the cage, the fry in the upper limelight is generally physically stronger, the individual is larger, and the fry in the lower limelight is worse, and the individual is smaller, so that the fry with different individual size and physical strength can be basically separated. in order to avoid the fry of individual size and strong physique crowding out the fry of individual size and weak physique, and gradually form the differentiation of size. However, in the course of operation, it is necessary to strictly prevent hypoxia in the cage so as not to cause losses.

6. Fish fry should be released slowly in deep water close to the surface of the water when entering the pond.

According to the experiment, when the fry is poured into the water from a height of 30 cm, it can be damaged by 5-10%; when it is 60 cm above the surface of the water, the damage rate of fry can reach 20-30%. Therefore, fish fry must be placed slowly and gently into the pond. Do not leave immediately after fish fry is released. Wait for fry to disperse and swim into the pond before leaving. If fry are found to be dense and clustered, they should be sprinkled gently with water droplets to make them disperse and swim into the pond. In case of windy weather, enter the pond in the upwind and deep water, so as to prevent the fish fry from being blown to the slope of the pool or pressed to the bottom of the pool and cause casualties.

7. Fish fry of the same species with the same specifications should be released in the same pond, and try to release them at once, so as to avoid the occurrence of big fish eating small fish and uneven specifications out of the pond.

When fish fry with different specifications are released together, the growth rate of large fry is much faster than that of small fry, and polarization is even more obvious.

8. The standard of self-hatching fish fry in the pond.

When you see two eye spots and one waist point, you can enter the pool when you can swim in parallel, otherwise you should feed the fish fry in time so as not to starve to death. When you go to the pond, choose a windless and sunny morning to avoid entering the pond on windy, rainy days or at night.