Detailed Explanation of Key Technical Points for Overwintering White Pomfret Fry
White pomfret is a freshwater fish species introduced to China for farming in the last century. Its flesh is excellent, it grows extremely fast, it is suitable for extensive farming, and it is easy to manage. Combined with strong market demand, it is deeply loved by consumers and farmers alike. However, it is a warm-water fish that needs to grow in water temperatures of 15-30 degrees. Once the water temperature drops below 12 degrees, it will freeze to death, especially the fry. Therefore, winter management is extremely important during farming. So how do white pomfret fry overwinter? Let's take a look.
1. Choosing a Site
When farming white pomfret, the water level of the breeding pond should be kept above 1.5 m, so that the water temperature can be maintained at 12 degrees in winter and the fry will not freeze to death. The area should be 2-4 mu, and it is best to have a site with ample sunlight, convenient water sources and shelter from the wind. If conditions permit, you may choose an area with abundant underground hot spring water in the pond bottom, which can perfectly solve the water temperature problem.
2. Building a Cold-proof Shed
Ordinary breeding ponds do not have underground hot spring water, so a cold-proof shed must be built during farming to allow white pomfret to overwinter safely. Many farmers now choose to build cold-proof sheds with small galvanized pipes, welding the small galvanized pipes with angle iron into a half-moon shape, fixing them on the pond embankment, and covering the welded frame with plastic film. The built area should cover half or one third of the entire pond. Many farmers also use rice straw and other crop straw to build them, or cultivate duckweed, algae and other aquatic plants on the water surface, all of which can play a cold-proof role. If there is an underground hot spring water farming environment, then there is no need to build any cold-proof measures.
3. Feed Feeding
The choice of feed and the feeding method are both key to whether white pomfret can overwinter safely. The feed fed should preferably be rich in crude protein, with a crude protein content above 30%. When the water temperature is above 20 degrees, feed twice a day, respectively in the morning and afternoon when sunlight is abundant, with each feeding amount at 4%-5% of the fish body weight; when the water temperature is 15-20 degrees, the water temperature is lower at this time and the activity of white pomfret is lower, so only one feeding per day is needed, and each feeding amount should also be lower than at 20 degrees, at 2%-3% of the fish body weight; when the water temperature is below 15 degrees, there is no need to feed. When feeding, it is best to feed at fixed times, in fixed amounts and at fixed locations, and also ensure the freshness of the feed. Do not feed rotten or spoiled feed.
4. Water Quality Management
The most important thing in farming freshwater fish is water quality management. In winter, the temperature is lower, microorganisms and bacteria in the water reproduce more slowly, and the metabolism of white pomfret is also slower, so the water quality easily becomes very clear, resulting in fewer nutrients in the water. At this time, fully decomposed organic fertilizer, such as pig manure or chicken manure, should be put into the water to make the water quality fertile, tender, lively and refreshing, and to speed up the growth of white pomfret.
5. Others
During farming, attention should also be paid to the prevention and control of diseases. Although the low temperature in winter makes the probability of disease occurrence lower, you should still not take it lightly. In winter, the diseases are saprolegniasis and ichthyophthiriasis. The prevention and control methods are pond clearing and disinfection before releasing fry, strengthening water quality management during farming, reducing farming density, and preventing fish bodies from rubbing while swimming, which can lead to pathogen invasion and infection. When saprolegniasis occurs, a low-concentration potassium permanganate solution can be splashed over the whole pond. Ichthyophthiriasis is a parasitic disease; when it occurs, dried chili peppers plus dried ginger slices can be boiled into a boiling soup and then splashed over the whole pond for treatment. When white pomfret overwinter, try not to disturb the fish school, so as to avoid frightening them and causing collisions that result in mechanical injury. Also, try to avoid using drugs such as trichlorfon, otherwise the whole pond may die.
The above is the full content of the overwintering techniques for white pomfret fry. We hope it can help you. To learn more about fish farming knowledge, please keep following us.