1 what is the requirement of pond water quality
cloudy and rainy weather often occurs in spring, and the air pressure is low, so the water body is easy to lack oxygen. The pond should be strictly cleared and disinfected, and there are many diseases of grass carp itself, so the intensive culture pond is more prone to epidemic diseases, and at the same time, the miscellaneous fish should be eliminated to avoid feed loss.
The pond is required to be far away from pollution sources, with an area of 5-1 mu, a flat bottom, loam as the best bottom material, and slight leakage as the best, with the bottom mud of 1-2 cm and the water depth of about 2 meters. In the case of dry ponds (with accumulated water of 5-1cm), 1kg of quicklime per mu is used for slurrying, or 1kg of bleaching powder per mu is used for splashing in the whole pond after being dissolved in warm water, so as to completely kill pathogenic bacteria without leaving dead corners. Sprinkle quicklime regularly, generally every half month according to the water depth of 2 kg per mu per meter, or use 1 ml of bleaching powder to splash the whole pool.
each pond should be equipped with a 3kW impeller aerator and a 4-inch water pump for timely water change and aeration. The pH value of water quality should be kept between 7.5 and 8.5, the transparency of pool water should be kept at about 3 cm from June to September, and the oxygen consumption of organic matter should be 18 ~ 2 mg per liter. Change the water by adding water in a planned way, and inject new water every 1 days, each time 2 ~ 3 cm. By mid-July, change the water according to the actual situation, and the change amount is 1/2. June to mid-August. Grass carp is prone to floating head due to lack of oxygen. Start the aerator for 2-3 hours at noon on sunny days, 3-4 hours in the morning and once in the middle of the night on cloudy days to prevent fish from floating head.
2 How to stock fish in dry ponds
After overwintering, the water quality of fish ponds is generally aging and weakly acidic. Therefore, when the water temperature of fish ponds gradually rises and stabilizes above 13℃ ~ 15℃, the water quality of fish ponds should be treated: replace the whole pond with 1/3 fresh water, and appropriately reduce the water level of the pond to facilitate the rapid increase of the water temperature of the pond; When the weather is clear, open the aerator for 1-2 hours at noon for ventilation, and use quicklime or microbial agents to improve the water quality of fish ponds as appropriate.
Grass carp species should choose individuals who are golden in color, harmless in appearance, lively and robust, and weigh about 1g. Because grass carp bleeding and enteritis are both easy to infect the current year's fingerlings, it is better to choose the second-year-old fingerlings. Before fish enter the pond, attention should be paid to body surface disinfection. When stocking, fish were soaked in 3% salt water to immunize grass carp.
the first time to release fish species is to release 25 grass carp with a tail weight of 15-2g per mu. Compared with high-density and large-scale stocking, this method can greatly reduce the cost of fish species and save 5% ~ 73%. On the other hand, it avoids the phenomenon of dead fish in the flood pool when the fish carrying capacity in the water body is too high during the high temperature period.
the other is to stock 8-1 fish per mu, with 1 silver carp and 15 herring with individual specifications of 25-5g, and not to match carp or less to avoid competing with grass carp.
3 what should be paid attention to in parent fish cultivation
After the spring, the water temperature in the fish pond rises gradually, and the fish begin to eat. At this time, it is necessary to start eating as early as possible and feed fresh and high-quality feed to ensure that the fish can start eating early, promote physical recovery, improve disease resistance, promote fish growth in time, accelerate the gonad development of parent fish, and improve the yield and efficiency of breeding.
Ying Qin patrolled the pond to avoid floating head in the pond. The parent fish that are pregnant with eggs have relatively high oxygen consumption, so it is necessary to keep the water quality in the fish pond with high dissolved oxygen. Once the water in the pond is short of oxygen, the parent fish will float, which will affect the maturity and spawning of the parent fish, and even lead to the failure of the parent fish, which will seriously affect the production throughout the year.
strengthen flushing to promote the development and maturity of parent fish. When the water temperature is stable above 15℃, strengthening the stimulation of water flow to the parent fish will help the parent fish to develop and mature, so that the mature parent fish can lay eggs smoothly.
Effectively control the occurrence of fish diseases. Excessive application of pesticides and excessive application amount will affect the mature spawning of parent fish, and even affect the quality of fry hatched from spawning. Therefore, the application amount of parent fish ponds should be strictly controlled. After wintering, some parent fish may suffer from frostbite and water mold, so it is necessary to catch the dead and sick fish in time to avoid polluting the water quality.
4 How to feed is scientific
The feed protein content is an important factor affecting the economic benefits of grass carp breeding. Practice has proved that when the feed protein content is about 3%, it can not only ensure the rapid growth of grass carp, but also reduce the feed cost, and the breeding benefits are the best.
The feed used for intensive culture of grass carp in ponds is mainly compound fish feed, supplemented by green feed. The compound feed is mainly made of fish meal, soybean meal, wheat bran, secondary flour, corn, refined grass and other raw materials, supplemented with compound additives of mineral salts, vitamins and amino acids, which requires comprehensive nutrition, including crude protein 2%, crude fat 4%, carbohydrate 4% and cellulose 8% ~ 1%. The green feed is fed with alfalfa, ryegrass, Sudan grass, dry grass, water grass and so on.
Feeding high-quality feed can make grass carp grow faster with fewer diseases, and the intensive pond should be fed with "fixed quality, fixed quantity, fixed time and fixed point". Conventional feed is fed 2-4 times a day from mid-March to May, 3 times a day from mid-June to mid-August, and 4 times a day from mid-August to October. Starting from June, feed green feed once a day, and the feeding amount should not be too large, and it is appropriate to take seven or eight to prevent satiety or hunger.
Grass carp is fierce and gluttonous, and if it is fed too much at one time, it is easy for the feed to swell in the intestine and kill the fish. Generally, the daily feeding amount is 1.5% ~ 1.8% of the weight of grass carp, and it is fed in three times. In order to prevent the polarization of individual growth caused by uneven feeding, the diameter of granular feed is 4 mm, and the feeding time should not be less than 45 minutes each time, so that all grass carp can get feed as much as possible.
5 How to prevent epidemic diseases
Carefully patrol the pond, grasp the activities and feeding status of fish in the pond in time, and grasp the changes of water quality, so as to achieve "early prevention without disease and early treatment with disease". Common diseases of grass carp include erythroderma, gill rot, enteritis, etc. Generally, the treatment method is combined with oral administration and external spraying, and the external spraying is mainly based on disinfectants such as bleaching powder and chlorine dioxide for 3 days. Oral administration of "Sanhuang powder" bait has a better effect. Every 5 kg of fish weight, .3 kg of "Sanhuang powder" (5% rhubarb, 3% phellodendron bark and 2% scutellaria root, ground into powder, and then stirred evenly) is mixed with flour paste and fed in the feed for 3-5 days.
sulfaguanidine can also be made into floating feed, that is, every 5g of sulfaguanidine is mixed with 1 kg of bran, and then 3 taels of elm bark powder or sweet potato powder are added, mixed with hot water, pressed into small pieces and dried for later use. The bait is mixed into the granules, and 1 gram of medicine is used for every 1 kilograms of pond fish on the first day, and the dosage is reduced by half every day on the second to sixth days. Once a day, 6 days as a cycle, every 1 month to 1.5 months for a cycle.
Some fish may suffer from frostbite and water mold after overwintering, so 1g of water mold net per mu can be sprinkled all over the pond, and gallnut juice can be sprinkled all over the pond; The drug bait feeding method can be used to prevent and treat enteritis; Poultry erythromycin containing 1 million units per gram can be sprayed with .7 million international units in the whole pond on the first day, and taken orally with the powder mixed with bait on the second day. One gram of erythromycin per 1 kilograms of fish can be halved in 2-6 days, which can cure rotten carp disease. Treatment of enteritis and gill rot complications with gallnut and furazolidone. The specific method is to use Chinese gallnut to boil the liquid medicine and sprinkle it all over the pool, and at the same time feed furazolidone for 6 days, 1 mg per 1 kg every day.