Four major problems to be solved in black fish culture

With the continuous development of the aquaculture industry, farmed fish has attracted more attention among many aquaculture projects, because the investment cost of fish farming is low, and the return is high, although there are certain risks, but compared with other aquaculture industries, the risk of fish culture is much smaller.

What is Blackfish?

The black fish has a cylindrical body with a length of up to 60 cm, a long head, a flat front end, a black body, a gray abdomen and irregular spots on the side of the body. The dorsal and anal fins are long and without hard spines, the ventral fins are very small, and the caudal fins are round. Blackfish often live in rivers and lakes, especially in flooded muddy areas. Black fish are ferocious, fertile and have a huge appetite. They can often eat all the other fish in a lake or pond. Blackfish can also glide on land, migrate to other waters in search of food, and can live out of water for as long as three days. As early as 2000 years ago, it was listed as the top grade of insects and fish by Shennong Materia Medica, stone honey, bees, beeswax (propolis), oysters, tortoise shells, mulberry tick octopus, sea clams, clams, carp and so on.

Black fish is a common edible fish in China, with large size, fast growth and high economic value. Black fish has less bone spurs, high meat content and rich nutrition, which is higher in protein than chicken and beef. As a medicine, black fish has the functions of removing blood stasis, nourishing and nourishing. After surgery, eating black fish has the effect of invigorating muscle and tonifying blood, promoting wound healing, and has very rich nutritional value.

Four major problems to be solved in black fish culture

In recent years, the black fish market is popular, and pond culture of black fish is gradually on the rise. In the case of the depression of carp culture, black fish culture has brought considerable economic benefits to fish farmers.

First, the pond to choose to cultivate black fish pond is not too large, the general area of 3 mu-5 mu is better. The water depth of the pond is 1.5-2.0 meters, the thickness of the sediment is 15-20 centimeters, the water source is sufficient, and the drainage and injection is convenient.

Second, the specifications for the release of fish species are determined according to the specifications of commercial fish in the market. At present, black fish weigh 0.7 kg-2.0 kg, so the specification of stocked fish should be 75 g-100 g per fish. Stocking density should be determined according to feed sources, feeding techniques and other factors. Generally, 2000-2500 fish fry are put in per mu. At the same time, it can raise 400-500 silver carp fingerling, and the specification is 100g-150g each.

Third, feed black fish is a ferocious carnivorous fish, eating both live food and dead food, mainly on 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, fish species can all 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.

Fourth, the feeding and management of black fish has 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 more serious, the method of killing part of the water surface can be taken, that is, the trichlorfon is sprinkled on the water surface of 2-3 meters on the edge of the pond with a concentration of 0.5ppm~1.0PPm. Black fish have strong disease resistance and seldom get sick in the process of artificial feeding. However, in the late autumn, black fish will also get sick, such as poor management, insufficient feed, serious poor water environment and so on. Therefore, this stage must be carefully observed, once the disease should be treated in time.

The living habits of Blackfish

1. Living habits: black fish are benthic fish, which live in a wide range of habitats. Therefore, where frogs, Loach, crucian carp and all kinds of aquatic insects live in groups are all places where black fish like to live. Black fish often lurk in shallow water with a depth of 1 meter. The living temperature of black fish is 0 ℃ 41 ℃, and the optimum temperature is 16 ℃ 30 mol. When the water temperature rises above 8 ℃ in spring, the black fish begins to move and swim from deep water to shallow water to look for food. It grows faster when the water temperature is above 20 ℃. When it is sultry and rainy in summer, it tends to jump out of the water and crawl on the wetlands on the shore. In autumn, when the water temperature drops to 12 ℃, stop feeding; drop to 6 ℃ and move to deep water. When the water temperature is too low in winter, it is buried in the mud to survive the winter, as long as there is water under the ice. Black fish can tolerate hypoxia. It can also survive in turbid and anoxic water. When there is a lack of oxygen in the water, the fish can put its head out of the water and use the organs on the gills to directly absorb the oxygen in the air for gas exchange.

2. Feeding habits: black fish is a fierce carnivorous fish. Mainly feed on small fish, shrimp, frogs and tadpoles, aquatic insects and other aquatic animals. The specific kinds of food consumed vary with the size, season and water environment of the fish. But in any case, it will not change the nature of its carnivorous nutritional type.

3. Growth: the fish hatched in that year are generally about 150 mm long and weigh about 50 grams. The body length of 2-year-old fish accelerated the growth stage and grew vigorously. After 2 years old, it showed a decreasing trend with the increase of age. When the water temperature is 20 ℃ and 25 min, the growth rate is faster.

4. Reproduction

The age of sexual maturity of ①: the Yangtze River valley is generally 2 winter years old, and the local area generally begins to mature and lay eggs in the third year.

The number of eggs conceived in ②: the average number of eggs carried by an individual is 10-30 000, and the largest is 50-60 000. The number of eggs is different in individuals of different ages and sizes and in different water bodies.

Feeding technique of black fish

1. Pond construction: choose the east-west direction, rectangular pond, the bottom of the pond is soil, the depth of the pond is 2-2.5 meters, the water depth is 1.5-2 meters, the inlet and drainage should be equipped with anti-escape facilities, and 100kg / mu of quicklime should be thoroughly disinfected 15 days before breeding.

2. Fish stocking: before entering the pond, the fish should be soaked in 3% to 5% salt water for 10 minutes for 15 minutes, and then put into the pond. The fish species with a body length of 10 centimeters and 14 centimeters will have a stocking density of 9000 million fish per mu and 16 fish species per mu, and the stocking density is 8000 fish per mu.

3. Daily management: pay attention to observe the feeding, activities, morbidity trend and environmental changes of black fish. Change the pool water 4 times a week in spring, a small change every 3 days in the high temperature season, a big change every 7 days, enter and drain to catch the escape net, and the pool ridge is more than 50 cm above the surface of the water. For the discharged sewage, the necessary sewage treatment should be carried out.

4. Feed feeding: feed for black fish, including artificial compound feed, small miscellaneous fish of fresh water or sea water, and scraps of livestock and poultry after slaughter. Before feeding, small miscellaneous fish need to be sorted to remove fish with hard spines, such as Pelteobagrus fulvidraco. Before feeding, use slapping as a signal to concentrate distant fish near the bait table to reduce feed waste. The initial feeding amount is 10% of body weight, and then it can be appropriately reduced to about 5% of body weight. It should be fed with one spoonful, so that the waste of feed is less. Feeding should adhere to the "four-fixed" principle, and each pond should choose 3-4 feeding points. The way of intensive culture is adopted, with a body length of more than 10 cm. After 8-9 months of culture, the survival rate is 75%-80%, the average body weight is 0.5-0.7 kg, and the yield per mu is 4000-5000 kg. Plant some aquatic plants in the pond, such as Rabdosia angustifolia, Sophora flavescens, water peanut, etc., and the planting area should be controlled at 1 / 3 of the pond area.

Although the aquaculture industry is developing well now, it still takes a lot of energy to achieve certain achievements in the aquaculture industry, just like black fish culture. before breeding, we should first understand some of its living habits and culture skills, so as to avoid unnecessary risks in the breeding process!