<h1>Practical technology for still-water aquaculture of flower eels</h1>
1 Water quality regulation of eel culture
Flower eels have higher water quality requirements. Ponds should be disinfected before breeding, generally using quicklime disinfection, using about 150 to 250 kg of quicklime per 667 m2 pond is appropriate, and at the same time it can improve the pH of pond water, if the pH value reaches more than 11, it can also remove wild fish, insects, etc. in the water, and improve the acidity of the soil at the bottom of the pond. After disinfection, the pond water is left to stand for 15 to 20 d, and its pH value is maintained between 8 and 9, and other fish are generally used for trial culture, and when the lime toxicity disappears, the eel is put into the eel after the trial culture has no problem.
In the process of breeding, the water quality should be kept clear and tender, and the appropriate amount of blue-green algae should be ensured in the water body, and the algae can play a role in shading, oxygenating and stabilizing water quality. If there are fewer algae in the water, the water body will become thin, which will have an impact on the feeding and growth of the eels, so the method of introduction or fertilization can be used in the breeding to promote the reproduction of algae in the water. In addition, regular inspections should be carried out, and if zooplankton are found in the water, they should be treated in time to prevent pollution of water quality and affect the growth of eels. Zooplankton can be killed with a b1 preparation of kervossis, sprinkled along the edge of the pool for about 2 m, and the zooplankton in the water can be controlled to ensure that the algae in the water is sufficient. In addition, it is also necessary to detect the dissolved oxygen, ammonia nitrogen, nitrite, pH value, etc. of the water quality, once the problem is found to be dealt with in time, such as the low dissolved oxygen degree in the water, the number of aerators should be increased, and the start time of the aerator should be extended to ensure that the oxygen concentration in the water meets the requirements.
2 Flower eel feeding management
The environment of water quality will have an impact on the feeding of eels, of which the impact of water temperature is more serious. If the temperature difference between morning and evening is large, it will affect the feeding amount of flower eels, and the temperature difference between morning and evening in the general pool should be controlled within 3 ° C. If the daily temperature difference exceeds 4 ° C, it will lead to less food intake of flower eels, at this time, it is advisable to minimize the amount of feeding and reduce it by 30% to 50%. In the process of breeding, it is necessary to strengthen the temperature control of the temperature difference change, such as pulling off the insulation shed late at the turn of spring and summer, and building the insulation shed in advance at the turn of autumn and winter, so as to avoid the impact of the temperature difference between the seasons on the feeding amount of the eel. In order to ensure the amount of eel food, generally according to the water temperature in the pool to control the feeding amount, such as when the temperature in the pool is between 24 ~ 29 ° C, the feeding amount is 2.5% ~ 3%, when the water temperature exceeds 30 ° C, the feeding amount should be reduced accordingly, down to 2.2% ~ 2.6% is appropriate.
In addition, as the flower eel grows, the amount of feeding should be increased accordingly. In the white seedling stage, the amount of white litter should be 5% to 6% of the body weight of the eel, and when the growth period is transferred to the black litter stage, the bait rate should drop to between 5% and 3.5%. The feeding amount of eels is also closely related to water quality, in the breeding process, the general amount of water can not be too large, water quality changes too much will lead to a serious decline in the feeding volume of eels, and even produce the phenomenon of non-feeding. Ammonia nitrogen, nitrogen nitrite and other substances in the water can not exceed the standard, harmful substances exceeding the standard will lead to the flower eel body itself oxygen delivery abnormality, resulting in irregular feeding of the flower eel.
3 Culture of flower eels
In China, the most commonly used way of breeding eel is open-air still water aquaculture, the scale of the general eel farm is suitable for control within 3.33 hm2, the breeding process should be improved in various infrastructure, such as ponds, water injection systems, auxiliary facilities, etc., and try to use natural water sources for aquaculture. In order to maintain the cleanliness of water quality in the breeding process, moderate water change should be carried out, and the amount of water per change should be maintained at 1/10 to 1/7 of the pool water, in order to improve water quality, it is generally necessary to rely on planktonic cyanobacteria, water wheels, and aerators to ensure that the oxygen in the water meets the demand. This culture method is less expensive, does not take much time to build the pond, and uses equipment for oxygenation, less electricity consumption, but the overall yield is low, generally 1 000 to 2 000 kg per 667 m2.
In the breeding to classify the flower eel pond, generally can be divided into 4 categories, the area of adult eel pond is the largest, generally the first level of the pond is mainly used for juvenile flower eel feeding training.