CATDOLL : CATDOLL: How to manage tilapia, grass carp and dace in fish ponds on a daily basis, prevent diseases and eliminate parasites, handle sludge and disinfect, and how often to change the water?

How to manage tilapia, grass carp and dace in fish ponds on a daily basis, prevent diseases and eliminate parasites, deal with sludge and disinfect, and how often to change the water?

(1) Choose the right fish species

Male tilapia grow fast, but if there are female tilapia in the fish pond, it will cause excessive reproduction of offspring, resulting in too high a density of fish per unit water body, which will not only affect the growth rate of the fish, but also waste feed and increase breeding costs. At the same time, if there are female fish in the pond, male tilapia will affect their growth due to nesting. Therefore, the selection of fish species should focus on the high male rate, while also taking into account the characteristics of high catch rate, growth and meat yield. (2) Suitable pond conditions

There are no strict requirements on the specifications of fish ponds for tilapia farming. The area can be large or small, and even small reservoirs can be used for farming. Tilapia is also an excellent choice for cage farming. The area of ​​commercial tilapia farming ponds should be 10 to 15 mu. If the pond area is too small, the water environment will be unstable, which is not conducive to material circulation; if the pond area is too large, it will be inconvenient for production operations. The water depth of the pond should be 1.5 to 3.0 meters. However, for tilapia ponds that need to spend the winter, the water depth is required to be more than 2.5 meters. (3) Preparation before stocking

① Repair the fish pond: drain the pond water in autumn, and remove pathogens and harmful organisms and improve the soil quality by freezing, drying and exposing to the sun; remove weeds and debris, dig out excess silt, level the pond bottom, repair the pond edge, reinforce the embankment, dredge the drainage channel, set up fish fences, etc. ② Clean the pond with drugs: drain the pond water, leaving 3 to 5 cm of water at the bottom of the pond, and use 60 to 75 kg of quicklime per mu, or 10 to 15 kg of bleaching powder (containing 30% effective chlorine) per mu, or 40 to 50 kg of tea seed meal per mu. Generally, pond cleaning should be done at noon on a sunny day to improve the efficacy of the drug. ③ Inject water and apply basal fertilizer: about 7 days after pond cleaning, wait until the toxicity of the drug disappears, and inject 0.5 to 1.0 meters of new water, and apply basal fertilizer to cultivate plankton and other bait organisms. After the tilapia fingerlings are put into the pond, as the water temperature rises and the fish grows, gradually add water to the maximum depth. (4) Stocking time

Under natural conditions, when the water temperature is below 18°C, tilapia generally stop feeding. Therefore, fish can only be stocked when the water temperature is above 18°C. If stocked too early, the low water temperature can easily cause death; if stocked too late, the growth period is shortened, affecting the size of the pond and the fish yield. Therefore, when stocking fish, the right time must be grasped. (5) Appropriate stocking density

The stocking density of fry is 5,000 to 20,000 per mu, and the stocking density of adult fish is 1,000 to 2,500 per mu. Usually, in order to ensure that larger sizes can be put on the market, the stocking density is 1,000 to 1,500 per mu. Tilapia is mainly used for fillet processing. Generally, fish weighing more than 400 grams can be put on the market. The larger the size, the higher the price. Therefore, it is recommended to raise large-sized adult fish for sale. (6) Reasonable combination of species

3-4 months after the tilapia fry enters the pond, 80-100 7-10 cm snakehead fry are placed per mu to control the offspring of tilapia reproduction; 30-50 bighead carp; 100-120 grass carp; and 10-20 black carp. Do not mix tilapia with other large-sized fish species during the fingerling stage to prevent them from competing with tilapia for feed. Tilapia weighing more than 100 grams will develop a habit of snatching food, and the impact of other large-sized fish species on them will gradually decrease. (7) Pay attention to drainage and irrigation

When adding water to the pond and draining water, special attention should be paid to prevent the entry of other wild tilapia, and dense net blocking measures should be taken to prevent tilapia from multiplying in large numbers in the fish pond. (8) Regularly turn on the aerator

Tilapia generally will not die due to floating, but it is also necessary to turn on the aerator to circulate the water between the upper and lower layers of the pond, prevent the tilapia from floating or floating in the dark, and reduce the extra nutrient consumption of the tilapia. When the weather is clear, turn on the aerator for 0.5 to 1 hour at noon, and turn on the aerator appropriately in the early morning depending on the specific situation. (9) Water quality management requirements

Tilapia is not very strict about the water quality. It feeds on plankton in the water. Relatively rich water can save feed. Therefore, the water quality required for tilapia farming is relatively rich, and the transparency of about 25 cm is better. Relatively speaking, the water quality required in the fish seed breeding stage is richer than that in the adult fish breeding stage. (10) Harvest in batches in a timely manner.

Tilapia that have reached marketable size should be caught and marketed in a timely manner, so that the water space can be fully utilized and the tilapia in the fish pond can continue to grow rapidly. (11) Anti-cold measures

Tilapia is not cold-resistant. To prevent the fish from freezing to death, the pond bottom should not be exposed to the sun too much before wintering, so that the tilapia can nest and live in groups for the winter. When winter comes, try to deepen the pond water, build a windbreak at the north corner of the pond, and raise water hyacinths on the water surface to prevent the water in the fish pond from flowing up and down, delaying the cooling time of the pond bottom. If conditions permit, renovate the fish pond and deepen the pond water to more than 2.5 meters. (12) Disease prevention and control

Fish disease prevention and control is one of the important links in pond fish farming, which determines the success or failure of farming. Therefore, we must conscientiously implement the principle of "comprehensive prevention, active treatment, and prevention is more important than treatment". The occurrence of fish diseases is the result of the interaction between the environment, pathogens and fish. To prevent diseases, we should adjust the water quality, control the spread and reproduction of pathogens, and reasonably manage the breeding to enhance the physical fitness of fish. When abnormal behavior of fish is found, the cause should be investigated immediately, and effective prevention and control measures should be taken to control the development of fish diseases. In terms of medication, we should prescribe the right medicine for the right disease, and we should not abuse drugs. We should avoid using organic matter, pesticides, heavy metals, antibiotics, furans and sulfonamides that are easily accumulated by fish and pollute the environment.