Detailed Explanation of Key Points of Snakehead Cage Culture Technology

In recent years, because of consumers' fondness for snakehead, the sales volume of snakehead on the market has risen rapidly, so farmers began to think about farming snakehead. The key point of snakehead farming is the culture technology of snakehead. As far as the current farming situation is concerned, snakehead cage culture technology is still quite popular.

Snakehead Cage Culture Technology

1. Cage specifications: cages for farming snakehead should be small rather than large. Generally, small cages of 15-33 sq m are used. The mesh size should be determined according to the size of the snakehead and the bait fish, and it should be small enough to prevent them from escaping through it.

2. Stocking density and specifications: stock 8-16 snakehead fingerlings of 5-150 g each per sq m. The specifications of snakehead fingerlings in the same cage should be uniform to avoid cannibalism when bait is insufficient. Stocking work is best completed before the end of April. If the seed sources are not concentrated, stocking can also be carried out successively.

3. Selection of snakehead fingerlings: at present, most snakehead fingerlings come from natural sources, so when selecting snakehead fingerlings, choose fingerlings caught with fishing gear such as dip nets, bamboo traps and Jiulong bags. Most of those caught with hooks are injured and should not be selected.

4. Setting up resting and hiding places: place some aquatic plants in the cage, with coverage not exceeding 70%, as places for snakehead to rest and hide.

5. Daily management: pay attention to observing snakehead feeding, activity, disease trends and environmental changes. In spring, replace 4/5 of the pond water every week. In the high-temperature season, do a small water change every 3 days and a large water change every 7 days. Install anti-escape nets at the inlet and outlet. It is better for the pond ridge to be more than 50 cm above the water surface. The discharged sewage should undergo necessary sewage treatment.

6. Feed feeding: the feed for raising snakehead includes artificial compound feed, freshwater or marine small trash fish, and offal left after livestock and poultry slaughter. Before feeding small trash fish, they need to be sorted, and fish with hard spines, such as yellow catfish, should be removed. Before feeding, use tapping as a signal to gather distant fish near the feeding table, reducing feed waste. The initial feeding amount is 10% of body weight, and later it can be appropriately reduced to about 5% of body weight. It should be fed one spoonful at a time, so that less feed is wasted. Feeding should follow the “four fixed” principles, and 3-4 feeding points should be selected for each pond. With intensive farming, for fish over 10 cm in body length, 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 cattail, tape grass and alligator weed, with the planting area controlled at 1/3 of the pond area.

Ecological Habits of Snakehead

1. Living habits: snakehead is a bottom-dwelling fish with an extremely wide range of habitats. Therefore, any place where frogs, loaches, crucian carp and various aquatic insects live in groups is a place where snakehead likes to inhabit. Snakehead mostly lurks in shallow water about 1 m deep. The survival temperature of snakehead is 0-41°C, and the optimum temperature is 16-30°C. When the spring water temperature rises above 8°C, snakehead begins to move and swims from deep water to shallow areas to feed. It grows relatively fast when the water temperature is above 20°C. In summer, when the weather is muggy and rainy, it often jumps out of the water and lies on the moist ground by the bank. In autumn, when the water temperature drops to 12°C, it stops feeding; when it drops below 6°C, it moves to deep water. In winter, when the water temperature is too low, it burrows into mud to overwinter, and as long as there is water under the ice, it can completely overwinter. Snakehead can tolerate low oxygen. It can also survive in turbid, oxygen-deficient water. When there is insufficient oxygen in the water, the fish can expose its head above the water surface and use the organ above the gills to directly absorb oxygen from the air for gas exchange. pH value: snakehead can generally live in both acidic and alkaline waters. Snakehead is good at jumping: its jumping ability is very strong, and it also jumps relatively high. When there is flowing water impact and rainfall, it is more likely to stimulate snakehead to jump and escape, and it often swims upstream against the current.

2. Feeding habits: snakehead is a fierce carnivorous fish. It mainly feeds on small fish, shrimp, frogs and tadpoles, aquatic insects and other aquatic animals. The specific types of food ingested vary with the size of the fish, season and water environment. However, no matter what, it will not change the nature of its carnivorous nutritional type.

3. Growth: fingerlings hatched in the same year are generally about 150 mm long and weigh about 50 g. The 2-year-old fish is in a stage of accelerated body length growth and grows vigorously. After 2 years of age, it shows a declining trend with increasing age. When the water temperature is 20-25°C, it grows relatively fast.

4. Reproduction

①Age at sexual maturity: generally 2 winters in the Yangtze River basin, and locally it generally begins to mature and spawn in the third year.

②Fecundity: the fecundity of an ordinary individual is 10,000-30,000 eggs, and the largest is 50,000-60,000 eggs. The fecundity of snakehead differs among individuals of different ages and sizes and among different water bodies.

Feed Formula for Snakehead

The formula feed for snakehead is made from the following raw materials in parts by weight: sorghum flour 20-25, cornmeal 15-20, soybean cake 20-25, fishmeal 10-14, snail powder 4-5, lotus root starch 3-4, spinach roots 5-9, celery roots 5-8, walnut kernels 2-3, tea tree flowers 4-5, Phellodendron chinense 2-3, water hyacinth 10-12, pickled mustard tuber 5-6, milk 8-10, phagostimulant 3-5, and an appropriate amount of water. The fish feed of this invention is prepared from a variety of materials, has a moderate nutritional ratio, and has the advantages of a simple production process, low cost, easily available ingredients and rich nutrition. It contains rich fat, carbohydrates, protein, vitamins, crude fiber and minerals and other nutritional components, meets the nutritional components required for the growth of snakehead, promotes the growth and development of snakehead, and reduces the incidence of disease in snakehead.

Prevention and Treatment of Common Snakehead Diseases

1. Saprolegniasis

Pathogen: Saprolegnia.

Symptoms: it occurs at all stages of snakehead growth. Early after infection, it is not easy to observe. When the water temperature rises back to about 18°C, it breaks out in large numbers; blood spots appear on the fish body surface, appetite decreases, the fish body becomes emaciated, melanin at the lesion site fades, a gray-white color appears, the luster becomes dim, and the fish swims alone away from the group. Finally, cotton-like white filamentous bodies grow out, and the muscles become turbid white until death.

Prevention and treatment: before stocking, use 100-150 kg/mu of quicklime for dry pond clearing. Adult fish ponds should be disinfected regularly with quicklime or bleaching powder; during the disease period, potassium permanganate can also be splashed over the whole pond at 30-50 g/m3. Care should be taken during fry and fingerling capture, transportation and handling to prevent injury to the fish body, and soak them in a 3%-5% salt solution for 10-20 minutes.

2. Red-skin disease

Pathogen: Pseudomonas fluorescens.

Symptoms: local bleeding on the fish body surface, loss of fish scales, especially on both sides of the abdomen, with fin erosion. The fish moves slowly, and sick fish often float on the water surface, weak and powerless. It often secondarily develops saprolegniasis until death.

Prevention and treatment: thoroughly clear the pond with quicklime to avoid injuring the fish body; disinfect with 0.5 mg/L Xiaoling or other chlorine-containing disinfectants, such as trichloroisocyanuric acid, sodium dichloroisocyanurate, chlorine dioxide, etc.; orally administer Yufukang and Yuxuekang, using 250 g per 100 kg of fish weight or according to the instructions, mix into feed and feed continuously for 3-5 days.

3. Hemorrhagic disease

Pathogen: various bacteria and viruses.

Symptoms: bleeding stripes perpendicular to the lateral line of the fish body appear on both sides of the body wall at the base of the pectoral fin and near the posterior edge of the gill cover; after bleeding symptoms appear, mass sudden death occurs in 3-4 days; outbreaks are likely from June to September.

Prevention and treatment: after winter fishing, thoroughly clear the pond. Bait fish need to be disinfected with salt water before feeding; splash formalin over the whole pond so that the pond water concentration reaches 20-30 ml/m3, or splash chlorine dioxide solution over the whole pond so that the pond water concentration reaches 0.5 g/m3, and repeat once after 4-6 days. Orally administer Yufukang No. 2, Yuxuesan or Yuxuekangtai, all according to the instructions.

4. Trichodiniasis

Pathogen: Trichodina.

Symptoms: it mainly harms the fry and fingerling stages of snakehead. It can occur all year round, but is more prevalent from April to July, with a suitable temperature of 20-28°C. Conditions such as small ponds, shallow water, poor water quality, insufficient bait, excessive stocking density and continuous rain make it easy to develop; sick fish have a lot of mucus, most or all of the fish body is white, swimming is slow, the fish body becomes emaciated, and death occurs from breathing difficulty.

Prevention and treatment: splash a mixture of copper sulfate and ferrous sulfate (ratio 5:2) over the whole pond so that the pond water drug concentration reaches 0.7 mg/L. It can effectively kill Trichodina on the body surface and gills of snakehead fry and fingerlings.

Snakehead cage culture technology is still relatively easy, and it is not very difficult even for people just starting out in the aquaculture industry. However, when farming snakehead, it is necessary to carefully observe the growth of snakehead every day, so as to prevent common snakehead diseases well. Otherwise, due to untimely treatment of snakehead diseases, mass death of snakehead may occur, resulting in loss of profits for farmers.