Detailed Explanation of the 80:20 Healthy Aquaculture Technology for Freshwater Ponds

Main measures of the 80:20 healthy aquaculture technology for freshwater ponds: First, select one species of food-eating fish with high market value as the main culture species (its output accounts for more than 80% of the total output), and stock about 20% filter-feeding fish as secondary culture species; second, scientifically feed high-quality pellet feed with comprehensive nutrition and good physical properties. The promotion and application of this technology can greatly increase the output of high-quality aquatic products, and can effectively overcome the problems caused by traditional pond polyculture models of feeding fresh bait, single raw materials, or mixed pellet feed with incomplete nutrition, such as increased pond sludge, easy deterioration of water quality, and susceptibility to fish diseases, thereby effectively reducing the pollution of pond aquaculture itself, avoiding water quality deterioration and the occurrence of fish diseases, and providing technical support for realizing a virtuous cycle of the aquaculture environment and doing a good job in healthy aquaculture. Channel catfish, Pengze crucian carp, grass carp, freshwater white pomfret, Heyuan red carp, eel, yellow catfish, loach, largemouth bass, mandarin fish and other species with high market value can all be stocked as main culture species, while filter-feeding fish such as bighead carp and silver carp can be used as secondary culture species to regulate water quality.
I. Pond Conditions
1. Pond: area 5-10 mu, water depth 2-2.5 m, firm pond embankment, good water retention. The pond bottom is flat, with little sludge, and a rectangular east-west orientation is preferable.
1.2 Water source: sufficient and pollution-free water source, water quality meets fishery water quality standards, convenient water intake and drainage.
1.3 Supporting facilities: complete electrical facilities, equipped with sufficient water filling and drainage equipment, and where conditions permit, one 3 kW aerator for every 6-8 mu of pond.
2. Preparatory work before stocking and stocking time
2.1 Pond clearing and preparation: before stocking fry, level the pond bottom and use quicklime to clear and disinfect the pond. For dry pond clearing, use 60-80 kg of quicklime per mu; for pond clearing with water, when the water depth is 1 m, use 150 kg of quicklime per mu; to kill pathogens and wild miscellaneous fish.
2.2 Fry stocking: the water temperature at stocking should preferably be below 10 degrees C, and stocking is generally completed before the Spring Festival. Before the fry are put into the pond, soak them in 20 ppm potassium permanganate for 5-10 minutes or in 3-5% salt water for 5-10 minutes.
3. Stocking model and requirements for fry quality and size
3.1 Requirements for fry quality and size: the fry are uniform in size, robust in constitution, and free of disease and injury. The size of the main culture fish is above 100 g per fish, and the size of the secondary culture fish is 50 g per fish.
3.2 The stocking model can refer to the following:
A. Channel catfish (Pengze crucian carp, Heyuan red carp and other main culture species) 100 g per fish, stocking density 850 fish per mu, planned adult fish size 600 g per fish, estimated output 450 kg per mu; B. Silver carp 50 g per fish, stocking density 100 fish per mu, planned adult fish size 750 g per fish, estimated output 60 kg per mu; C. Bighead carp 50 g per fish, stocking density 50 fish per mu, planned adult fish size 1200 g per fish, estimated output 40 kg per mu; total, stocking density 950 fish per mu, estimated output 550 kg per mu.
4. Feed nutrition, quality requirements and feeding technology
4.1 Feed nutrition must be comprehensive and balanced, the protein content of adult fish feed is above 32%, the protein content of fry feed is above 36%, and the water content is below 10%. Compound pellet feed is preferable, and either sinking or floating pellets are acceptable. The feed processing quality meets standards. It has good stability in water, and the raw materials are required to be fresh. In the early stage of adult fish rearing, it is best to choose feed with a protein content above 36%.
4.2 Feeding technology:
(1) Feeding amount: the feeding amount should be determined according to water temperature, water quality conditions, etc. The stocked main culture species begin to feed above 5 degrees C, and the feeding intensity is greatest at 25-30 degrees C. Each feeding should reach the point of eight-tenths full, and at the same time the feeding situation of the fish should be checked. Sinking feed should preferably be finished within 15 minutes, and floating feed within 30 minutes, with feeding twice a day. The specific feeding amounts are as follows:
When the average fish body weight is 50 g, the feeding rate per feeding is 3.5% of body weight;
When the average fish body weight is 50 g, the feeding rate per feeding is 3.5% of body weight;
When the average fish body weight is 100 g, the feeding rate per feeding is 3.2% of body weight;
When the average fish body weight is 150 g, the feeding rate per feeding is 2.9% of body weight;
When the average fish body weight is 200 g, the feeding rate per feeding is 2.6% of body weight;
When the average fish body weight is 250 g, the feeding rate per feeding is 2.3% of body weight;
When the average fish body weight is 300 g, the feeding rate per feeding is 2% of body weight;
When the average fish body weight is 400 g, the feeding rate per feeding is 1.6% of body weight;
When the average fish body weight is 500 g, the feeding rate per feeding is 1.5% of body weight;
When the average fish body weight is 600 g, the feeding rate per feeding is 1.4% of body weight;
When the average fish body weight is 50 g, the feeding rate per feeding is 3.5% of body weight;
(2) Feeding method: feed should be given according to the “four fixeds”, namely fixed time, fixed location, fixed quality, and fixed quantity. It is preferable to feed once each in the morning and afternoon every day. The feeding location is best fixed on both sides of the pond, and the range should be as large as possible to increase the feeding opportunities for smaller fish.
5 Water quality monitoring and management
5.1 Add water at the proper time and regulate water quality: the water quality should be kept fresh, with transparency preferably at 30-35 cm, and dissolved oxygen in the water maintained above 5 mg per L. To prevent water quality from aging, new water should be added regularly. From June to August, add 20-30 cm of new water every 10-15 days. Every 20-30 days, splash 10-15 kg of quicklime dissolved in water over the whole pond to regulate water quality. In the high-temperature season of July to August or in rainy and low-pressure weather, attention should be paid to changes in dissolved oxygen in the water. If dissolved oxygen in the water is found to be below 3 mg per L or signs of fish floating head are found, the feeding amount should be appropriately reduced, and the aerator should be turned on in time to increase oxygen.
5.2 Daily management: persist in patrolling the pond every day, observe fish feeding and growth, and measure water temperature. Check fish growth once every 7-10 days, and adjust the daily feeding amount once every half month. There are many factors affecting the feeding amount. In addition to water temperature and water quality (dissolved oxygen, pH, etc.), the physiological condition of the fish itself, weather, and feed palatability also have a great impact on feed intake, so it must be handled flexibly and fed reasonably. In order to keep complete data, archives should be established for each pond, and daily management work such as fish pond records should be done well.
6. Disease prevention and control
In implementing the 80:20 healthy aquaculture technology for freshwater ponds, the use of drugs is not advocated during the culture process, so strengthening disease prevention and control work is very important. Throughout the entire culture process, prevention should be given priority, management should come first, and comprehensive prevention and control should be implemented. Measures to prevent fish diseases, in addition to general work such as pond disinfection and fry disinfection, also include always maintaining pond environmental sanitation, strengthening water quality monitoring, not feeding spoiled feed, and regularly carrying out drug prevention and control, for comprehensive prevention and control.