1. Selection and cultivation of parent eels: The fat and strong eels are selected as parent eels, and the male and female parent eels are cultivated separately according to the ratio of 2: 1, during which silkworm pupae can be fed. 2. Incubation: When the water temperature is 25-28℃, inject chorionic gonadotropin solution into the parent eel, then put the female and male parent eels into the spawning pond according to the ratio of 2: 1, and keep the water temperature at 22-28℃ after the female eels lay eggs. 3. Water quality regulation: inject water 1 time every week, and plant some radishes appropriately.

1. Selection and cultivation of parent eel

1. When selecting the parent eel, it is required that it is fat and strong, bright yellow in body color, swollen and soft in lower abdomen, obvious in ovarian outline, light orange in abdomen and red and swollen in reproductive mouth. Male eels are generally about 50 cm long, while female eels are generally about 25 cm long.

2. After selecting the parent eels, separate the female eels from the male eels according to the ratio of 2: 1 or 3: 1, clean and disinfect the parent eel pond before breeding, and then put 20-25 parent eels per square meter.

3. Animals such as artificially tamed silkworm chrysalis can be fed during the breeding period, and fresh water is injected from time to time to adjust the water quality and keep the water depth at 10-25cm. Change the water twice a week, and the amount of water changed each time is 1/3, so as to ensure that long-term micro-flow water is beneficial to stimulate the normal development of Monopterus albus gonads.

4. At present, the parent eels used for artificial breeding are generally caught from reservoirs, lakes and other waters with tools such as hairpins and eel cages. Because of the special sex reversal phenomenon of Monopterus albus, it may be difficult to completely distinguish between male and female.

Second, spawning and hatching

1, ovulation induction

(1) After the water temperature reaches 25-28℃, the parent eel is injected with chorionic gonadotropin solution (for induced labor). The injection amount of each female eel is generally 400-500 international units (IV), and the injection amount of male eel can be halved. Generally, intraperitoneal injection is the best injection method, which not only has good effect, but also has short onset time.

(2) After the drug is injected, the female parent fish and the male parent fish are put into the spawning pond according to the ratio of 2∶ 1 or 3∶ 1, and generally the female parent fish can lay eggs (or squeeze out eggs) by themselves after 45-50 hours.

(3) If artificial insemination is to be carried out, the eggs of female eels should be collected in advance (squeezing eggs or taking eggs by laparotomy), and then the male eels should be dissected to take out their semen before dry insemination.

2. Incubation management

The incubation temperature of (1) eggs is generally 22-28℃. In a suitable temperature range, the hatching rate will increase with the increase of temperature. If the water temperature is about 25℃, the incubation usually takes about 150 hours (7-8 days), and the body length of the newly hatched eel fry is generally 12.

(2) After 3-4 days' incubation, the eel fry can be put into the nursery pond for cultivation. It should be noted that the water temperature difference between the incubation pond and the nursery pond should not exceed 3-5℃.

Third, raise seedlings.

1. Put eel fry into a nursery pond, feed zooplankton such as cladocera, copepods and some large rotifers after the yolk sac slowly disappears (about 7 days), then mix the cooked egg yolk and soybean meal into paste and feed them, or process the blood and leftovers of mussels, earthworms and various animals into paste, and then sprinkle them into the nursery pond.

2. The feeding frequency is 4-6 times/day, and the daily feeding amount is 2-5% of the weight of eel fry. If the stocking quantity is 450-500 per square meter, 20-40 standard eel species can be harvested after winter.

Fourth, water quality supervision.

1. Eel fry are resistant to sewage, hypoxia and diseases, but if intensive cultivation is carried out with high density, attention should be paid to adjusting the water quality. Generally, water can be injected 1 time every week, and washing water can also be changed 1 time, and the water exchange rate is 1/3 of the total pool water.

2. After summer, radish, mushroom, water bamboo or water bamboo can be planted in the nursery pond to shade the eel.

3. A proper amount of loach seedlings can be put in the nursery pond, generally 30-50 pieces can be put per square meter, which can not only clean up the leftover food of eels, but also regulate the water quality, and also avoid entanglement between eels.

V. Prevention and treatment of eel diseases

1. Generally speaking, prevention is the main method to prevent eel diseases. Before the eel fry enter the pond, it can be cleaned and disinfected in advance, and at the same time, it can be effectively prevented from getting sick by bathing with salt water (the appropriate concentration is 3-4%) for about 2-5 minutes.

2. The disease that is easy to occur when raising eel seedlings is generally water mold. The main cause of this disease is that eel fry bite each other or are attacked by enemy creatures, resulting in wounds on their bodies, and then the wounds are infected by water mold, thus getting sick.

3. A layer of white hair usually appears on the body surface of eel fry infected with water mold, commonly known as? White hair? Or? White fault? . After the onset, the eel fry showed impatience, loss of appetite, muscle rot in the affected area, and finally died of emaciation. If the eggs are infected by water mold, a large number of deaths will also occur.

4. When dealing with water mold, 400g of salt and 400g of sodium bicarbonate (commonly known as baking soda) can be used per cubic meter of water, and then the water is poured into the whole pool for 3 days.

5. If eel eggs are infected, they can be soaked in malachite green solution (0.7ppm) 10- 15 minutes for 3 days.