What do you need to pay attention to when raising eels in a net box

The eel nature like temperature, wind, light, afraid of shock. Therefore, the net box culture should choose the sun, wind, water convenient, outside interference, area of 3-5 acres, water depth of about 1.5m, the water level is relatively stable pond. Before eel stocking, the pond should be thoroughly disinfected with quicklime 100-120kg/mu to kill harmful microorganisms in the water and improve the substrate.

Second, the net box put off

Net box area of 15-20 square meters, net box with polyethylene mesh production, rectangular six-sided box, box height 1.5m, length, width depending on the pond, net box set in the middle of the pond, the corners of the four corners of the bamboo fixation, four sides of the bamboo with the bamboo frame, bamboo and bamboo junction of the corners of the live section, so that the water up net box can rise, the water can be under the downfall. The net box sinking depth of 1.Om or so, the upper edge of the net box from the surface of the water 0.5m, in order to prevent eels from escaping, and do a good job of the daily management of the buoy. The total area of the net box to not more than 50% of the pond area is appropriate. In the eel stocking 1 week before, the first net box into the water, let the net box attached to some algae, in order to avoid the eel body and mesh friction caused by damage, at the same time, the box put a good water peanuts, water hyacinth, oil grass and other breeding

faster aquatic plants, eel seedlings to the stocking to create a good environment for growth. The area covered by water plants is 80%-95%, if the growth of water plants is slow, you can apply appropriate fertilizer or urea to promote growth. Fertilizer is good for cultivating good water quality which is fat, alive, tender and cool, which is good for improving the survival rate of the eel fry and opening the food earlier.

Three, eel seedling stocking off

Currently, eel seedling from the capture of the wild seedling to the cage is preferred. Where catching, fishing and anal reddish eel species suffering from enteritis disease should be firmly removed. Eel seedling body color is generally best in yellow, that is, the dorsal side of the eel seedling was dark yellow and with black-brown spots, green eel followed by gray eel is not suitable for eel species. Stocking time: the first half of April-July, the temperature of 20 ℃ -25 ℃ is the most suitable, June-July is the best stocking period. Temperature more than 30 ℃ stocking, affecting the survival rate of eel species, eel species specifications to 20-40 tails per kg is appropriate. In the second half of the year, it is appropriate to stock the eel fry that year, after wintering as the next year's seedling. When stocking, the size must be divided into boxes, the same net box requires uniform size, each net box one-time stocking, stocking density of 1-2kg per square meter.Before stocking, the seedlings are soaked in 20 minutes of water using Shen Cao Dan 20mL/m3+Jin Weixin 20g/m3 to repair the mucus on the surface of the body and disinfection treatment to improve the physical quality of the seedlings and the ability to resist stress, and to increase the survival rate of the seedlings in the box and open the food earlier.

Four, baiting and feeding

The first eel species put into the net box must be tamed. The method: the first 3 days before the eel seed stocking first do not feed, to be eel action normal, in the evening began to lead the food. The bait selection eel favorite earthworms, small fish, mussels, etc., to take a small number of meals, and then gradually every day ahead of the feeding time, until the normal ingestion. In this stage, you can mix and serve the bait with health care drugs such as Pioneer of Food Attraction, Li-Stomach Bulk, and Jin Wei-Su to improve the neatness of the eel fry. After the eels form a good feeding habit, you can start to slowly add artificial pellet feed in the eel bait **** with feeding, take the first less and then more, gradually adapt to the policy of gradually increasing the proportion of artificial feed, the final proportion control in 1kg fresh bait with feed 1-2kg, feeding 2 times a day, to 6-7am, 5-6pm is appropriate. The total amount of feeding should be 2-3% of the eel's body weight at the beginning, and then gradually increased to 6%. The feeding method is good with gradual feeding. Fresh small fish and other fresh bait purchased from the market should be washed before feeding, and at the same time, every kilogram of fresh bait should be added with lmL of Shen Cao Dan to be soaked and sterilized for half an hour, in order to kill the pathogenic bacteria carried outside.

Five, daily management off

The net box breeding eel water to have a certain degree of fertility, transparency control in the 15-20cm between, the water color is too clear to affect the growth of eels. In order to improve the water quality, improve the utilization rate of the pond, outside the box should be timely set of crucian carp, silver carp, bighead carp, grass carp, etc., set of crucian carp at the same time can also remove the eel's enemy. Usually observe diligently, regularly check the bottom of the box, found dead eels should be fished out in time, once the net box rupture and eel morbidity, immediately repair and treatment. Summer high temperature period, eel feeding exuberant, excretion, water quality is very easy to corruption, this stage should be water quality control and prevention of summer heat mainly. Remove the residual bait in time every day, clean the net clothes if necessary, change the bottom water when changing water, for some water quality is poor, the bottom of the pool is aging and there is no water to change the place, we should often use the sea in the treasure powerful

Purification of water quality. The water plants in the box should also often remove the aging part, promote the growth of new grass, enhance the water purification function of water plants. In the fall, the water temperature begins to slowly decrease, the water plants begin to aging, so should be fished in time to remove the aging water plants, and leave 1/7 of the surface of the water for sunshine, in order to improve the water quantity, improve water quality. In winter, the water temperature drops, the water plants age and rot, the breeding density increases, the water quality deteriorates, resulting in a significant decline in the immunity of eels, so it is particularly important to add an appropriate amount of gold vizarin and other drugs in the bait before wintering to improve the disease resistance of the fish body. At the same time in the winter period using strong poison net, God grass Dan, kill poison king disinfectant for water disinfection, the sea in the treasure to purify the water quality should not be ignored, in order to ensure

Eel safe wintering.

Sixth, scientific disease prevention

In the eel breeding process must be in line with the "no disease early prevention, disease first treatment, prevention is more important than treatment" of the twelve words policy, often oral liver particles JinWeiSu and other health care drugs to improve fish immunity, the regular use of disinfectants to disinfect the water body, oral sterilization, deworming drugs The disease can be prevented and treated.

The causes of eel disease are many, summarized in the following aspects:

(1) eel pool causes: just built a new eel pool, did not soak in water for a period of time, the water quality has not been stabilized, and then immediately put the water to raise eels, so that eels can not quickly adapt to the disease. Or the old eel pool for a long time not clean and tidy, too much humus, the water quality is corrupted, to the pathogen reproduction to create a good condition.

(2) sudden change in water temperature: eels are suitable for survival in 15℃-30℃ water temperature. Due to the eel pool area is small, day and night water temperature changes, hot summer season, the water temperature is sometimes as high as 40 ℃ or more, often eels will be "hot" phenomenon. In addition, because of the eel pool to often refill the new water, the amount of water is too large to cause sudden changes in water temperature, thus affecting the growth of eels, such as the water temperature drop difference of about 4 ℃, eels are very easy to trigger a "cold".

The sudden change in weather

is also likely to induce disease.

(3) Harmful substances over the standard: the high-temperature season, feeding a large amount of eel excretion, the bottom of the pool deposited a large number of organic matter, the decomposition of organic matter will consume a large amount of oxygen in the water, resulting in a lack of oxygen. The organic matter is forced to anaerobic decomposition, producing a large amount of ammonia, hydrogen sulfide, methane and other harmful gases, while anaerobic bacteria take advantage of the situation to reproduce a large number of infected eels, resulting in disease.

(4) feeding technology causes: eels like to eat fresh bait, such as once put down unclean or rotten feed, will cause eel disease. If the feeding amount is not enough, or tame food is not complete, eels will appear to kill each other.

(5) improper use of drugs: eels for scaly fish, its physiological characteristics, resistance to drugs and scaly fish have a great difference, if the disinfectant, soaking drugs too strong irritation, will destroy the eel surface mucus, eel body and immunity to decline, it is very easy to be invaded by harmful bacteria in vivo to cause disease. Prevention of internal medicine, should be health care medicine, herbal medicine, from the perspective of enhancing the eel body, increase immunity to prevent.

Seven, disease diagnosis

The main characteristics of the eel disease are: abnormal activity, epidermal local hemorrhage and inflammation, the body color becomes green and black, the amount of food decreased or refused to eat and so on. Visual inspection is one of the main methods of checking eel disease, but also to be observed and questioned on the spot.

(1)On-site observation: sick eels tend to be thin, black body color, slow activity, swimming alone from the hole; some eels in the pool to show the state of restlessness, jumping up and down, rapid and wild swimming or entangled with each other. This may be harmful substances caused by madness disease or intestinal parasitic disease.

(2) body surface inspection: timely fishing out sick eels or just dead eels, in turn, from the head, mouth, eyes, body surface, eel tail and other careful observation. Easy to see some large pathogens, such as water mold; small pathogens, the naked eye can not be seen, but according to the performance of the disease

symptoms to be identified, such as the eel body green and black, oral congestion, anus red and swollen protruding, mostly enteritis; eel body exterior localized congestion and inflammation, the appearance of soybeans or nibbles the size of the red spot, when the epidermis is serious, the epidermis was a small nest of funnel-shaped, rotting is the erythromelalacia; rotting by the external, for the print disease; Part or all of the body surface by the mud coating a layer, for the mopping disease; born with the old cotton wool-like white material, often water mold disease, and so on.

(3) visceral examination: dissect the eel body, obtain the intestinal tract, cut from the foregut to the hindgut, observe whether there are parasites, the intestinal contents of the normal nature of the intestinal contents, and then rinse the dirt and feces with water, such as found in the intestinal tract all or part of the congested, purplish-red color, then the enteritis disease. If the liver and kidneys are congested and enlarged, and the color is black, white or florid, it is hepatomegaly.

In the daily breeding process, eel outbreaks are often comprehensive diseases, so in the confirmation of the disease must be carefully observed, scientific diagnosis, to find out the main symptoms, and then the right medicine

Eight, disease prevention and control

1, madness disease

The cause of the disease: stocking density is too large, the eel surface secretion of mucus to make the water microorganisms accelerate the decomposition of the water, the consumption of dissolved oxygen in the water. Dissolved oxygen in the water, so that the eels due to lack of oxygen and restlessness, entangled with each other, the seedling body by a strong stress reaction, resulting in weakening, physiological disorders

and caused.

Epidemic time: Mostly in late spring and early summer and other weather unstable period of the fry.

Symptoms: sick eels do not eat food, sometimes sick eels in the net box in the shape of an arrow to swim quickly or winding water plants on the mouth open, the whole body muscle trembling and shivering. When the water is clear, you can also see the sick eel is "S" or "o" shape rotating struggle, body stiffness, body surface mucus reduction, no obvious trauma.

Treatment: 0.5mL of concentrated glutaraldehyde per m3 of water (equal to 0.5mL of strong toxicity net + 1g of gold vizarin) is splashed in the box once a day for 2-3 times. At the same time, internal use of each kg of feed to add JinWeiSu 5g + septic granules 5g + liver particles 5g, 2 times a day, for 5-7 days.

Prevention: After the seedlings are placed in the box, disinfect the box by splashing with concentrated glutaraldehyde 0.5mL+Kinvitin 1g per m3 of water, once a day for 1-2 days.

Precautions: when using the medicine, first use water to splash wet water plants in the box, then splash the diluted solution, and then rinse with water.

2, erythema hemorrhagic disease

Cause: unstable weather, breeding density, serious deterioration of water quality, fish immunity is reduced, the bacterial proliferation and bacterial infection.

Epidemic time: It occurs mostly in the seasonal exchange period when the weather is unstable or in the adult eel culture period from mid-September to before winter.

Symptoms: The surface of the body is covered with blood spots of different shapes, and sometimes there is diffuse hemorrhage all over the body, especially in the abdomen. In severe cases, the eel is covered with hemolytic red blood spots, bleeding from the mouth, red and swollen anus, enlarged and blackened liver, enlarged gallbladder, and congested abdominal cavity.

Treatment: per m3 water body with concentrated glutaraldehyde 0.5mL + strong poison net 0.5mL box splashing disinfection, once a day, for 2-3 times. At the same time, internal use of each ks of feed add JinWeiSu 3g + bacteriophage particles 4g + super red poison 2g, 2 times a day, for 5-7 days.

Prevention: frequent external disinfection with Kill King, Shen Cao Dan, Concentrated Glutaraldehyde, etc., and timely oral bacterial toxin extermination granules, Jin Wei

Su, septic granules and so on