Three measures for safe overwintering culture of black fish

Although the value of black fish has gradually been recognized by more and more people, and more and more people have raised black fish, people who have raised black fish all know that black fish are suitable for warm environments. Once the temperature gets colder in winter, the management and breeding of black fish will be much more difficult.

Three measures for safe overwintering culture of black fish

The benthic fish of the blackfish family, the suitable temperature for survival is 1 ℃ ~ 36 ℃, the suitable water temperature for growth is 13 ℃ ~ 30 ℃, and the optimum temperature for growth is 25 ℃ ~ 28 ℃. When the water temperature drops below 6 ℃ in autumn, the black fish swims slowly and often lurks in the depths of the water; when the water temperature is too low in winter, it hides in the bottom mud. During the overwintering period, farmers think that black fish do not eat or eat less feed, but relax management, it is easy to have a large number of black fish death (small size fish species is especially serious). Therefore, in order to ensure that fish species survive the winter safely, the following work must be done:

I. Scientific feeding

The main results are as follows: 1. in order to make feed relatively reasonable, we should not only ensure that the black fish are full, but also take into account that the culture environment is not polluted and save costs, so scientific feeding must be carried out. Less when the water temperature is below 15 ℃, not when the water temperature is below 8 ℃, more when the wind and sun is warm, not when the pressure is low in strong winds and rainstorms, and more when the water quality is good, but not when the water quality deteriorates.

2. After entering the autumn and winter season, the water temperature begins to decrease, and the stress to black fish is great, so anti-stress additives such as VC and VE should be added to the diet of snakehead. VC and VE can enhance the immunity of disease resistance, promote growth and improve the survival rate. Before feeding, the amount of VC 1.5g / kg feed and VE 0.1g / kg feed was dissolved into clear water (0.2kg / kg feed water 0.2kg / kg feed water), stirred evenly and fed with feed adsorption. Commercial multivitamin preparations can also be added to the feed, and the usage and dosage are according to the product instructions.

3. After the beginning of the spring of the second year, the temperature gradually rose and the black fish began to eat, but because the digestion and absorption function of the black fish in early spring was in the recovery period after shrinkage, its function was not strong enough, the weather changed repeatedly, the temperature went up and down, the cold air was active frequently, the water temperature was unstable, and the water quality of the pond all affected its food intake. The feeding amount should be determined according to water temperature, specifications of black fish, pond water quality, weather conditions, feed type and other conditions, and excessive feeding should be avoided.

Maintain good water quality

1. A stable water level of more than 1.5 meters under the ice should be ensured during the overwintering period. Ponds with serious leakage are not suitable for overwintering ponds.

2. Maintain the fatness of the pool water. In order to maintain a proper fertility of the overwintering pool water, the photosynthesis of phytoplankton can be used to maintain a relatively rich dissolved oxygen in the water; if the water quality is found to be discolored, turbid, blackened and fishy, it indicates that the water quality has deteriorated and new water needs to be replaced in time; after it snows during the overwintering period, it is necessary to sweep the snow on the ice in time to make the ice transparent. To ensure the normal photosynthesis of phytoplankton.

3. When the cage is used for overwintering of 1-year-old fish, the open type should be changed into a closed type, the food table in the box should be removed, and the cage should be sunk to the bottom of the pond (ditch). At the same time, the height of the water in the pool (ditch) should be 50 cm higher than the upper end of the cage. Pay attention to remove the snow on the ice in time after the snow to make the ice transparent.

4. After the beginning of spring, in the weather of low temperature, overcast and rain in spring and sudden cold and hot weather (cold air comes frequently), a large number of algae in the pond are easy to die, the water quality becomes bad, and when it is serious, it will stink, resulting in serious hypoxia. In this case, new water should be injected or changed in time. Quicklime (20,30kg / mu) can be regularly sprinkled in the whole pond, which can be sterilized and disinfected, agglomerate suspended substances, and play a certain role in regulating water quality.

Third, do a good job in the prevention and control of fish diseases

Give priority to prevention and combine prevention with prevention. In the process of culture, some water quality improvers, sediment improvers and microbial preparations are often used, which can be used better with live bacteria and better water quality. Disinfect the aquaculture water body regularly, sterilize and kill insects, and cut off the horizontal transmission of pathogens, it is best to use disinfectants that are non-irritating and non-residual to fish (such as bleach, salt, quicklime, fish bacteria net, fish bacteria, etc., and herbal medicine), and feed bait regularly to enhance the physique of fish and improve their ability to withstand disease and keep out the cold. Overwintering fish ponds should be kept quiet to prevent livestock from falling into ponds and causing fish unease. In order to avoid water mildew and dead fish, minimize fishing or dumping during the overwintering period.

The living habits of Blackfish

1. Black fish is a wild fish, which exists in many rivers, lakes, reservoirs, streams and canals in the south and north of China. In some places in the south, there are also special artificial stocking, but all of them are separate ponds. If there are several black fish in someone's fish pond, the fry in that pond will definitely suffer. The black fish is violent and fierce, known as "overlord in the water", but it is actually a harm to the fish pond.

2. Blackfish is a fierce carnivorous fish. In the juvenile stage, zooplankton is the main food, while adult fish specializes in small fish, shrimp, insects, Loach and frog.

3. Strong vitality, tolerance to hypoxia and strong ability to adapt to the environment. Individual size, fast growth, maximum body length up to 2 meters, weight up to 100 kg pond water dried up, black fish drill into the wet soil, can survive for two or three months, once there is water can be resurrected as before.

4. belong to the middle and lower class fish, often hiding in stone crevices, secluded places or weedy places, waiting for opportunities to catch prey. In summer, they often go to the surface to bask in the sun, and in winter, they dive into the underwater mud or artemisia residue to spend the winter.

5. Black fish like to live in lakes, reservoirs, rivers, ditches and ponds with lush aquatic plants and soft mud. They usually lurk at the bottom of the water, and only move to the upper and middle layers of water when they feed or lack oxygen in the water. Black fish have strong adaptability to bad water quality, water temperature and hypoxia. In addition to the Gill, the respiratory organ of the black fish also has an auxiliary respiratory organ (suprabranchial organ). When there is a lack of oxygen in the water, it can put its head out of the water to breathe oxygen in the air directly.

How to raise black fish

1. Pond selection

The pond for black fish culture should not be too large, and the general area should be 0.2~0.33hm2. The water depth of the pond is 1.5m ~ 2.0m, the sediment is thick 15~20cm, the water source is sufficient, and the drainage and injection is convenient.

2. Release of fish species

The specifications for the release of fish species are based on the specifications of commercial fish in the market. At present, black fish weight 0.7~2.0kg is a good seller, so the specification of stocked fish should be 75g / 100g. Stocking density should be determined according to feed sources, feeding techniques and other factors. Generally, 2000,500 fish fry are released per (667m2). At the same time, it can raise 400-500 silver carp fingerling, and the specification is 100g-150g each.

3. Feed feeding

Black fish is a ferocious carnivorous fish, eating both live and dead food, mainly eating wild miscellaneous fish such as crucian carp. Regular and fixed-point domestication and feeding methods were adopted in artificial feeding. Feed twice a day, 10:00 and 3 p.m. In general, all the fish species can float to the surface for food after 5-7 days. When feeding, you should carefully observe the eating situation of black fish near the table. For example, when there are few black fish near the table and the rush for food is not intense, it shows that the fish is full and can stop feeding.

4. Feeding and management

Black fish have a large diet and a lot of excrement, which can quickly fatten the pond water. Fertilizer and water can make plankton multiply in large numbers, which can easily cause hypoxia in the pond water. Therefore, special attention should be paid to the changes of dissolved oxygen in the water. In the event of hypoxia, the aerator should be turned on in time. If the hypoxia is serious, the method of killing on part of the water surface can be adopted, that is, the trichlorfon can be sprinkled on the 2m water surface near the pond with a concentration of (0.5 × 1.0) × 10 ~ (- 6).

The benefit of black fish culture

Black fish has well-developed auxiliary respiratory organs, tolerance to hypoxia, tolerance to fertilizer and water, and will not die from water for a long time, so it is suitable for high-density culture. The yield of black fish culture is high, and the economic benefit is remarkable. The general black fish fry yield is about 750kg/67 fish, the output value is about 13500 yuan, and the adult fish yield is about 450kg/67 fish, the output value is about 7200 yuan.

The profit of black fish culture mainly depends on the market price of black fish, the price of bait and whether the culture is successful. Black fish fry rearing is generally fed with expanded pellet feed, the weight gain cost per kilogram is about 10.5 yuan, including hydropower, fish medicine, feed, etc., and the feed coefficient is about 1; when feeding bait fish, the general feed coefficient is 3: 4, the size of the feed coefficient mainly depends on the advantages and disadvantages of the bait fish, and the weight gain cost per kg depends on the market price of the bait fish. Adult fish culture is generally fed with feed fish, the feed coefficient is 3-4, and the weight gain cost per kilogram is the same as that of fry.

In a word, the economic benefit of black fish culture is not immutable, the benefit of black fish fry cultivation is about 5000 yuan / 67 fish, and the benefit of black fish adult fish culture is about 1500 yuan / 67 fish.

No matter what kind of things are bred, it is very necessary to master its living environment. Only by mastering its living environment can we create waters suitable for them to live in. In order to constantly update the existing technology, the development of the cause of aquaculture is getting stronger and stronger, in order to make the road of aquaculture become wider and wider.