Hotel Freshwater Fish Breeding Technology

3. Breeding technology

The key aspects of freshwater fish breeding technology are mainly water quality control, feed quality and feeding methods, and disease prevention and control.

1. Water quality

Aquaculture water is a very complex system with various ionic molecules dissolved in the water, including various microorganisms, plankton and other aquatic organisms. These substances interact and restrict each other, and their content determines the quality of water, which has a huge impact on aquatic animal breeding.

Water quality control mainly includes detection and water quality regulation. Factors that affect changes in water quality include: water source, water exchange volume, oxygenation facilities, stocking density, fertilization, feeding amount, substrate, etc. The water quality requirements are as follows:

(1) Dissolved oxygen: 3~7 mg/L. Although tilapia can tolerate hypoxia below 1 mg/L, when the dissolved oxygen is lower than 3 mg/L for a long time, the fish The state will be abnormal and prone to disease. In pond culture, the dissolved oxygen in the water fluctuates day and night. Under normal weather conditions, the highest point of dissolved oxygen occurs at 2-3 noon. The dissolved oxygen in the upper layer is mostly in a supersaturated state, and the lowest point is around 3 a.m., but if the water If it is too deep, hypoxia may also occur at the bottom of the pool during the day. When dissolved oxygen is insufficient, "high-concentration polymerized oxygen" 500g/mu 1 meter water depth or "special large particle oxygen" 500g/mu 1 meter water depth should be used promptly.

(2) Transparency: Normally, the transparency of water is determined by the amount of plankton. Because tilapia can make good use of and digest phytoplankton, a certain concentration must be maintained in the breeding water, especially in the early stages of breeding. If the water quality is too clear, it is best to apply fertilizer, and use "Compound Water Culture King" 5 acres/pack Or "Biological Water Cultivation King" 3-5 acres/bag to keep the water transparency at 30-40cm.

(3) Water temperature: The growth temperature ranges from 10 to 34°C; generally the most suitable greenhouse temperature is 26 to 32°C. Tilapia stays below 10℃ for a long time.

(4) Ammonia nitrogen: 0.1~0.3 mg/L. When the ammonia nitrogen is too high, it is recommended to change part of the water if possible, and use "Water Protecting and Detoxifying Spirit" or "Ecological Water Protecting Spirit" in time "500g/acre in water depth of 1 meter to remove toxins, then put in the oxygen-enhancing product "Dr. Oxygen" 500g/acre or "Bottom Oxygen King" 500/g meter and quickly put in "Compound Water Culture King" or "Algae Probiotic" for fertilizer and water.

(5) PH value: 6.5 ~ 8.9; Under normal circumstances, the water source should be comprehensively monitored and evaluated before breeding. For farmers, water temperature, transparency, and Ph value, dissolved oxygen, ammonia nitrogen and other water quality conditions. In addition, during the breeding process, the stability of the water quality must be maintained. When changing the water, do not drain and irrigate the water, but change it frequently and frequently. There should not be too much difference between the pond water and the new water.

2. Feed and feeding

Tilapia has a wide range of food habits, including aquatic and terrestrial plants and animal feed (such as earthworms, fly larvae, small insects, etc.), which come from many sources. Wide and low price. However, in order to improve feed utilization, reduce water pollution, and speed up growth, we should choose compound feeds with low feed coefficients and good quality, and cultivate natural feeds (phytoplankton is preferably diatoms and green algae, and can also eat cyanobacteria) ). When setting up a feed table, the amount of feed should be based on the feeding data, and should be adjusted appropriately according to fish dynamics, weather conditions, water temperature, water quality, etc. Feeding should not be too fast or too slow. Feeding too fast will lead to waste of feed and residual organic matter. Feeding too slow will lead to fights between the species of fish and cause damage. Each feeding time is different for each fish, usually 15 to 30 minutes.

The number and time of daily feeding should be determined, and the error in feeding time should not exceed 30 minutes; a feed table should be set up as a feeding point in a place where fish often appear, and the feed should be spread as far as possible. If the pond is large, the tilapia can be domesticated by banging the bucket, hitting the water, clapping, etc.; in special circumstances such as rainy days, hot weather, abnormal fish activities, etc., the amount of bait should be appropriately reduced. As the fish grows, Gradually increase the amount of feeding; at the same time, select a brand of feed and do not switch to other brands of feed at will. Ensure the quality of the feed, and do not feed odorous or spoiled feed.

During the breeding process, we recommend that "Baochangan" and "Healthy Growth Partner" or "Yien" be often added to the feed. Regularly adding "Yikanglu" and other drugs to feed can improve the disease resistance and growth rate of fish.

4. Disease prevention and control

The occurrence of fish diseases is the result of the interaction between the environment, pathogens and fish bodies. To prevent diseases, we must improve water quality and control The spread and reproduction of pathogens, reasonable feeding and management, and enhance the physical fitness of fish.

When fish are found to have abnormal behavior, the cause should be immediately investigated and effective preventive measures should be taken to control the development of fish diseases. In terms of medication, it is necessary to prescribe the right medicine, not to abuse drugs, and to eliminate the use of organic matter, pesticides, heavy metals, antibiotics, furans, sulfonamides and other drugs that are easily accumulated by fish and pollute the environment. The common diseases include 1. Bacterial fish diseases: gill rot, enteritis, saprolegnia, streptococcosis, vertical scale, etc. 2. Parasitic diseases: Chlamydia, trichozoa, anthyloidosis, and third-generation worm disease. , fish disease and so on. China Organic Agriculture Network