Snakehead fish farming technology video tutorial, teaching you how to scientifically raise snakehead fish well

The snakehead fish is a rare freshwater fish of high economic value, known as the “treasure among fish.” It is extremely nutritious, containing a large amount of protein, more than that found in chicken and beef. From a nutritional standpoint, the snakehead fish is a comprehensive-nutrition, delicious-meat premium health food. The snakehead fish sells well both domestically and internationally, commands a high price, and is one of China's important aquatic products for foreign trade export; in the domestic market it is also a scarce and expensive food.

The living habits of the snakehead fish

1. Living habits: The snakehead fish 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 the snakehead fish likes to inhabit. The snakehead fish mostly lurks in shallow water about 1 m deep. The survival temperature of the snakehead fish is 0-41°C, with the optimum temperature being 16-30°C. When the water temperature rises above 8°C in spring, the snakehead fish begins to become active, swimming from deep water to shallow areas to feed. It grows faster when the water temperature is above 20°C. On stuffy, hot, rainy summer days, it often leaps out of the water and lies prone on the moist ground along 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. When the water temperature is too low in winter, it burrows into the mud to overwinter, and as long as there is water beneath the ice it can overwinter completely. The snakehead fish can tolerate low oxygen. It can also survive in turbid, oxygen-poor water. When the water is short of oxygen, the fish can expose its head above the surface and, using the organ above its gills, directly absorb oxygen from the air for gas exchange. pH value: The snakehead fish can generally live in both acidic and alkaline waters. The snakehead fish is good at jumping: its jumping ability is very strong, and it jumps quite high. When there is flowing water impact and rainfall, it is even more easily stimulated to jump and escape, and it often swims upstream against the current.

2. Feeding habits: The snakehead fish is a fierce carnivorous fish. It mainly feeds on small fish, shrimp, frogs and tadpoles, aquatic insects and other aquatic animals. Depending on the size of the fish, the season and the water environment, the specific types of food it takes in differ. But no matter what, its nature as a carnivorous nutritional type does not change.

3. Growth: Fry hatched in the same year generally reach about 150 mm in length and about 50 g in weight. The 2-year-old fish is in an accelerated body-length growth stage, growing vigorously. After 2 years of age, it shows a declining trend as age increases. It grows faster when the water temperature is 20-25°C.

4. Reproduction

① Age of sexual maturity: In the Yangtze River basin, generally 2 winters of age; locally, they generally begin to mature and spawn from the third year.

② Fecundity: 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 fish differs among individuals of different ages and sizes and among different water bodies.

Artificial breeding of the snakehead fish

1. Selection of broodstock: The quality of broodstock is the key factor in artificial breeding. The snakehead fish selected should be over 2 years of age, and individuals weighing 500 g-1500 g are more suitable. Broodstock that have already reached sexual maturity, have no disease or injury on the body, and are large in size with good growth performance should be selected.

2. Identification of male and female broodstock: Male and female snakehead fish have no obvious secondary sexual characteristics, and they are sometimes difficult to distinguish in appearance. During the reproductive season: the female's abdomen is enlarged and soft, the genital pore is slightly red and somewhat protruding, and the abdomen is grayish-white; the male's abdomen is smaller, not as soft as the female's, and the genital pore is slightly sunken.

3. Artificial induced spawning: Broodstock are paired in a 1:1 ratio, and the broodstock are placed directly in a spawning pond to wait for natural spawning, or artificial induced spawning can be carried out. The suitable area of the spawning pond is 0.1-3 mu; it is best for the pond bottom to have a deep part and a shallow part, 1 m and 0.3 m deep respectively, with grass planted or placed in the pond, and greater transparency with lean water is preferable. Spawning can also be carried out in the broodstock rearing pond. For artificial induced spawning, broodstock whose gonads have developed to the end of stage IV should be selected, the water temperature should be 25-28°C, and the general time is from late May to mid-June. For artificial induced spawning drugs, chorionic gonadotropin and carp pituitary are more effective. Pituitary: 4-6 per kg; chorionic gonadotropin: 1600-2400 international units; halve for males. For those with poor maturity, two injections can be given, with an interval of 24 hours. The injection site is intracoelomic injection. At 23-30°C, after 18-25 hours, the broodstock can spawn and fertilize automatically.

4. Artificial incubation: After the broodstock spawn and fertilize in the spawning pond, they can be scooped out with a small fish-basin hand net and concentrated into an incubation pond or other container for incubation. Generally, 500 eggs are placed in a washbasin, 5000-8000 eggs in a large plastic basin, and 10,000-20,000 eggs per sq m in a small cage net. Generally after 2-3 days, fry can be hatched, shaped like small tadpoles, with a grayish-white body, using their own yolk as nutrition. After 4-5 days, when the yolk is fully absorbed, live water fleas must be fed immediately. The amount of water fleas put in depends on how much the fry eat, and it is better to give small amounts many times. After 5-6 days of feeding, the fish body turns yellow, with a total length of about 1.5 cm. They can then be moved to a small pond for rearing. Issues to note in incubation.

① Pick out dead eggs at any time to control water mold infection. After 10 hours, eggs found to be white are unfertilized eggs; pick them out.

② Before placing eggs in the incubator, disinfect with 0.1 ppm malachite green pond water. Use after 24 hours.

③ Keep the water quality clean, and pay attention to changing the water. Once a day, to prevent oxygen deficiency.

④ Just after hatching, do not change too much water, to prevent excessive temperature changes. On the day of hatching, the amount of water changed accounts for 60-70% of the total water volume; from the second to the fifth day, the amount of water changed accounts for 80%; the water temperature change should not exceed 2°C. The incubation water temperature is best controlled at 24-30°C. In still water at 25-28°C, incubation takes about 33-38 hours to hatch, and at 23-25°C about 36 hours.

Fry and fingerling rearing

It is generally believed that “snakehead fish are easy to hatch but hard to rear,” with a high fry survival rate of 70-80%, and a low one of about 20% or even total loss. There are two rearing methods: one is to rear the fry and fingerlings in one go; the other is to rear them in two stages, fry and fingerling.

Domestication and rearing of larvae

Newly hatched fry are 3.8-4.3 mm, floating on the water surface and using their own yolk sac as nutrition. They are much more delicate than the fry of Chinese major carps, and management is more difficult. Therefore, they should first be domesticated and reared for a few days in plastic basins, small cement ponds, plastic-film “earth ponds” or the original incubator, and moved into fry rearing ponds only after they can swim in groups and chase zooplankton for food. During domestication and rearing, generally in a cement pond about 60 cm deep, 13,000 larvae are placed per sq m. After 3-5 days, the yolk sac disappears and they begin to take feed, so food should be given immediately. At first, feed 3 ml of egg yolk liquid (egg yolk weight plus 1 part water, stirred evenly) three times a day. Rotifers, cladocerans, and copepod larvae (filtered through 32-40 mesh silk bolting cloth per sq cm) can also be fed, with the smaller ones used for feeding. After 4-5 days of domestication and rearing (that is, the 9th-10th day after hatching), when the fry are yellow in body color, can swim freely (can sink and can swim to the surface) and gather in groups to feed, the fry should be successively moved into larger rearing ponds or cage nets for fry rearing.

Fry rearing (body length 3-4 cm)

1. Cement pond: ① Rectangular, square, or round are all acceptable, but rectangular is generally better. 4-8 sq m is suitable, with a water depth of 0.6 m. ② Disinfect and fill with water. ③ Stocking density: 400-800 fish per sq m. ④ Feed: They still feed on zooplankton, and need to be fed rotifers and water fleas to satiation; when natural feed is insufficient, artificial feed should be added. After 2 weeks, the reared fry have grown slightly and their food intake doubles; at this time, large crustaceans and chopped tubifex can be fed, once each morning and evening. After the 20th day, minced low-quality miscellaneous fish meat can be used for feeding. ⑤ Rearing management: Adjust water quality; normal dissolved oxygen is above 3.2 ml per cubic meter, and when it is below 2.4 ml per cubic meter, the fry begin to die. Separate and rear them in time. After 3 weeks of rearing, they generally reach 3-4 cm; sieve and separate them in time. But at the latest this must not be delayed until before they reach 5-6 cm. At 5-6 cm they begin to prey on small fish and shrimp, and when food is lacking, the large eat the small.

2. Pond rearing: ① Disinfect the pond and apply base fertilizer. The area is 100-300 sq m, with about 100 sq m being generally suitable. ② Stocking density: 60,000-80,000 per mu, with a water depth of 0.6-1 m. ③ Fertilize and feed. ④ Daily management. Patrol the pond, add water at the proper time, and use a seine to separate and rear them.

3. Cage net rearing: ① Materials: nylon, plastic bolting silk; area 1-10 sq m, height 0.5-0.8 m, water depth 0.3-0.6 m. ② Cage net installation: Make a frame from wood or bamboo, fix the eight corners to the frame, and the whole cage net can rise and fall with the water; install it in a fish pond with fertile water quality, abundant feed, convenient management and shelter from wind. ③ Density: about 4000 fish per sq m. ④ Feeding and daily management are the same. After 5-6 days of rearing, separate them into different cages for rearing.

4. Causes of fry death during the nursery period: ① Lack of sufficient palatable feed. In the early stage of fry rearing, because the stocking density is high, the fry lack the needed suitable palatable feed organisms, such as cladocerans, copepods, rotifers, water fleas, etc., often causing massive death. In the middle and late stages, because animal feed is insufficiently fed, the fry grow unevenly and cannibalize each other, decreasing day by day. ② Oxygen deficiency. Because the water body for rearing fry is small and the density is high, dissolved oxygen is insufficient; on cloudy days when air pressure is low, this causes prolonged floating at the surface and leads to death. ③ Sudden weather changes. In midsummer when the water temperature reaches above 30°C, during heavy rain the pond water temperature changes greatly, most easily causing massive death.

Fingerling rearing

After the fry grow to 3-4 cm, their feeding habits begin to change, and they need more food and a larger activity space. If they are still kept in the original pond, the density will be too high, which will affect the growth of the fish. Therefore, a fingerling rearing stage is generally needed, continuing to rear the sieved inch-size fry until the winter of the same year, growing them into fingerlings about 10 cm or larger, and then putting them into various polyculture ponds or raising them alone as food fish. However, there are also places that directly use small ponds to rear the tiny fry into fingerlings about 10 cm.

1. Preparatory work before stocking: The basic conditions of the fingerling pond are roughly the same as those of the fry pond. Generally, a large earth pond is used for rearing, with a pond area mostly of 0.5-1 mu and a water depth of 0.5-1.5 m. Before the inch-size fry are put into the pond, the pond should undergo a series of work such as clearing, disinfection, fertilizing and water cultivation.

2. Fingerling stocking: When zooplankton in the pond have multiplied in large numbers, stock the sieved, uniformly sized inch-size fingerlings (3-4 cm) into the pond at 20,000-50,000 per mu.

3. Feeding: After the summer fry are put into the pond, topdressing is still needed to cultivate water quality and breed zooplankton for the fish to eat. As the fish gradually grow and their feeding habits change, relying only on the zooplankton in the pond can no longer satisfy their feeding needs. Therefore, sufficient feed must be fed, and the amount of animal feed should be gradually increased. Every day, chopped small miscellaneous fish, small shrimp or fresh water fleas should be fed, generally 3-4 kg per 10,000 fish per day. Gradually, miscellaneous fish viscera, bones, etc. can also be smashed and mixed with wheat flour and stirred before feeding. Feeding chopped small fish and shrimp is best. Generally after September, the fingerlings can grow to more than 10 cm. In the following year, adult fish farming can be carried out.

Adult snakehead fish farming

Adult snakehead fish farming refers to the production process of rearing various sizes of fingerlings into food fish in small water bodies such as ponds, bay ponds, water pools and cage nets. Artificial snakehead fish farming includes two types: extensive polyculture and intensive monoculture. Extensive polyculture refers to polyculture with the four major Chinese carps, etc. in a fish pond; intensive monoculture is high-density monoculture using abundant water sources, sufficient feed and conditions. It is divided into cage net monoculture and pond monoculture. In recent years, our city has mainly adopted pond high-density monoculture. A brief description follows, for reference only.

Pond high-density monoculture

1. Preparatory work before farming

① Farming facilities: earth ponds, cement ponds, etc. The water depth should be 1-2 m. Water-lifting equipment should be complete.

② Water source: river water, reservoir water, underground well water, etc. are all acceptable, and the water quality should preferably be neutral or weakly alkaline.

③ Area: To facilitate production management and sales, the fish pond area should preferably be smaller, best about 1 mu, and should not exceed 2 mu at most.

④ It is best to have water inlet and outlet openings. Anti-escape facilities such as 40-60 cm netting must be set around the pond.

⑤ Plant aquatic plants on the water surface around the pond, generally not exceeding about 20%, as hiding places, to facilitate shading from sunlight, escaping the heat, and predation, while also purifying water quality and regulating water temperature.

⑥ Before stocking fingerlings, pond clearing and disinfection must be done well.

2. Farming technology

(1) Fingerling stocking: ① Fingerling size: Select fingerlings of the current year over 10 cm (preferably 14-20 cm, 60 g-100 g); the fingerlings must be uniform in size, with no injury or disease. ② Fingerling source: It is best to choose locally produced fingerlings. ③ Stocking time: For the current year, it is best from September to early October, so they can feed and recover their constitution and improve the overwintering survival rate. Stocking after the new year is in March-April. ④ Disinfection: Before entering the pond, they must be strictly disinfected, generally by soaking in 5% salt water for 10-15 minutes or in 10 ppm malachite green solution for 10 minutes. ⑤ Stocking density: At a depth of 1.2-1.5 m, stock 8000-9000 fish per mu for fingerlings of about 50-60 g, and 5000-6000 fish per mu for fingerlings of 80-100 g; if the average water depth decreases, the stocking amount decreases accordingly.

(2) Feeding management: Feeding must adhere to the “four fixeds.” Before feeding, use tapping sounds as a “signal” to form a “sensory” response, gathering the snakehead fish around the feeding ground, which easily forms a feeding frenzy, increases food intake, and reduces feed waste. The feed types are mainly fresh animals, mainly marine and freshwater small miscellaneous fish and shrimp. In freshwater there are Hemiculter leucisculus, wheat-ear fish, sand loach, young fish, small crucian carp, small tilapia, Rhodeus, small qingtiao, small freshwater shrimp, etc.; in seawater there are sardines, herring (yellow croaker) and various small miscellaneous fish. During the peak feeding season, the amount of bait is about 8% of the fish weight, and can reach more than 10% at the highest. In the off-season, it is 3-4%. For the feeding method, using “slow, fast, slow” gives good results and less feed waste; after most of the fish have eaten their fill and swim away, feeding can be stopped. The quality of the weather, the air pressure, and the water quality make a big difference to the fish's food intake.

(3) Daily management: Mainly do the following aspects well. ① Pond patrol: Observe the fish's feeding, activity, water quality changes, whether there are signs of floating at the surface, whether there are diseased fish, etc., and deal with problems promptly when found. ② Water changing: The snakehead fish takes in high-protein feed every day, so the ammonia concentration in the pond water is relatively high, especially in summer when the water temperature is high, and the water body very easily deteriorates. For this reason, the water body needs to be changed in time, generally changing 1/3 every week and 4/5 every half month, with flexible control according to water quality changes. Where conditions permit, it is best to maintain micro-flowing water farming, and during the farming period the water temperature should preferably not exceed 30°C. ③ Anti-escape: In the early stage of stocking snakehead fish fingerlings, the fingerlings are still small and their jumping ability is relatively poor. As they gradually grow, their jumping ability increases considerably, especially on rainy days when changing water or in the early morning, when jumping is very active. Therefore, the height of the pond ridge from the water surface should generally be greater than 50 cm, sturdy anti-escape nets must be installed at the water inlet and outlet, and anti-escape nets or anti-escape walls must be installed around the pond.

3. Common fish diseases and their prevention and treatment

① Water mold disease: Prevention and treatment method: Be as careful as possible during operations such as netting, transport and stocking to prevent injury to the fish body; use 0.1 ppm malachite green or 0.5 ppm methylene blue for whole-pond disinfection. When fingerlings are affected, they can be soaked in 10 ppm malachite green or a 3-5% concentration salt water solution.

② Enteritis disease: Prevention and treatment method: Mix 34 g of furazolidone into 100 kg of feed and feed twice a day for 3 consecutive days.

③ Myxosporidiosis: Prevention and treatment method: Treat with 90% crystallized trichlorfon at a concentration of 0.2-0.5 ppm.