CATDOLL : CATDOLL: How do tilapia survive the winter?

1. How do tilapia survive the winter?

Tilapia is a tropical fish with poor cold tolerance. When the water temperature drops below 12-13℃, it will gradually freeze to death. In order to continue breeding and producing tilapia the following year, a certain number of broodstock and fingerlings must be preserved to ensure their safe wintering. The water temperature in most parts of my country is below 10℃ in winter. Except for Hainan, Guangdong, Guangxi and parts of Taiwan, most other areas cannot naturally overwinter. Therefore, different methods should be adopted according to local conditions for wintering. When the water temperature is stably maintained above 18℃ the following year, the fish will be put back into the breeding pond and the culture pond for normal reproduction and growth. The current wintering methods for tilapia in my country include wintering with hot spring water or deep well water, wintering with waste water from power plants (factories), wintering with factory-style greenhouses, wintering with plastic greenhouses, wintering with artificial heating (electricity, coal), wintering with pond fences, and wintering with geothermal water pumps. The main methods are:

(1) Using geothermal energy to survive the winter

Geothermal water can be hot spring water or deep well water. Using hot spring water or deep well water to survive the winter is the most ideal, with low investment and good results. The scale of the pool must be based on the minimum water supply available throughout the year. The water temperature must be above 20°C, and it is best to use a self-flowing hot spring. In places where there are no hot springs, deep well water can also be used to survive the winter. As long as the water temperature is above 20°C, it can survive the winter and preserve seeds. If the water temperature drops due to a cold current, the number of water changes must be increased to keep the water temperature above 16°C. (2) Using factory waste heat to survive the winter

Cooling water or waste steam discharged from thermal power plants or steel mills can be used as heat sources. As long as the water temperature is kept above 20°C, the water quality is non-toxic, and the water source is sufficient and continuous, a pond can be built for wintering. The requirements are the same as for wintering with hot spring water. Under the condition of sufficient waste heat source, the water temperature can be adjusted to above 25°C, and a certain amount of feed can be fed. Tilapia can not only survive the winter, but also grow normally, and fish diseases will be greatly reduced accordingly. (3) Using solar energy for wintering

Any glass greenhouse, plastic film greenhouse, or greenhouse with solar energy device can be used to overwinter tilapia according to local conditions. (4) Heating overwintering

When the temperature is low, a tea stove, boiler or electric heating device is used for heating. This method is relatively costly and is often used for small-scale seed preservation over the winter.

2. How to keep tilapia through the winter

Tilapia is a tropical fish, and its most suitable water temperature for growth is 25-35℃, and its lethal temperature is below 10℃ (usually it dies when it is below 7℃). After entering winter, the death of tilapia mostly occurs two or three days after the temperature drops suddenly. When the temperature rises again, a large number of deaths will occur, and some will die intermittently for several consecutive days. There are two main reasons:

1. Death from illness After entering winter, tilapia will experience large-scale deaths. Death often occurs after the water temperature changes from cold to hot (warming up). According to long-term experiments by scientific and technological workers, when environmental factors such as water temperature, salinity, dissolved oxygen and pH value change, they will more or less produce adverse stimulation reactions on fish. When the feed lacks certain vitamins or minerals (such as vitamins A, E, B1, B2 and zinc), it is easy to induce fish diseases. When the water temperature drops to the lower limit of the survival temperature (2-3 days), tilapia will not freeze to death immediately, but its activities will slow down and it will stop eating. Therefore, there is little accumulation of vitamins and trace elements in the fish. When the water temperature warms up, tilapia activities become more active. When the body is unable to meet the needs of survival due to insufficient nutrients, pathogenic bacteria also become active due to the rising water temperature. Tilapia's immunity decreases due to insufficient nutrients, and it is susceptible to pathogens and parasites, and it will be infected and die.

2. Death by freezing: When the water temperature drops to the lower limit of the survival temperature of tilapia, if it is frozen below 7°C for many consecutive days (5-7 days), a large number of tilapia will be frozen to death.

Prevention and control measures

1. Fattening and strengthening Before winter, fattening and strengthening measures should be strengthened to enhance the fish's ability to resist disease and cold. Before winter (autumn) and during the winter, it is recommended to feed complete nutritional feed, which is the basis for ensuring the comprehensive nutrition of fish. Only by eating complete nutritional feed can the accumulation of vitamins and inorganic salts (such as minerals) in the fish's body meet the needs of maintaining life activities.

In this way, even if the water temperature drops, affecting the fish's food intake, the accumulation of various nutrients in the fish's body is sufficient to enhance its ability to resist cold, and it can also survive the winter smoothly.

2. Fish disease prevention and control During the winter, fish are generally not caught by nets to avoid damaging the fish surface and causing bacteria and diseases. Tilapia is malnourished and the fish body is frostbitten due to low water temperature. Pathogenic bacteria invade and are prone to Saprolegniasis and red skin disease. The fish body is injured due to low temperature and is easily invaded by parasites, such as Ichthyophthirius, Oblique tube worm, Wheelworm and other diseases, which cause the fish body to die due to weak resistance. Therefore, it is necessary to disinfect the aquaculture water regularly, such as adding 20 kg of quicklime per acre per meter of water, or 1 kg of bleaching powder, or fish bacteria clearing (used according to the instructions) to dissolve water and spray it all over the pond; if there is a parasitic disease, use a mixture of copper sulfate and ferrous sulfate 0.7 ppm (5:2) to dissolve water and spray it, and use one of them in turn every 15-20 days to achieve the purpose of sterilization and insecticide.

3. Feeding with medicated bait During the winter, when the water temperature rises to 18-20 ℃, you can use the fish medicine "Yubikang" mixed with nutritious feed to feed the fish. Feed the medicated bait once every 10 days to replenish the fish's physical energy and enhance its disease resistance. The fish will be strong and its ability to resist cold will be correspondingly enhanced.

4. Do a good job of winter cold prevention: ① Deepen the pond water to keep warm. If conditions permit, deepen it to more than 2.5-3 meters. The deeper, the better the heat preservation. ② Appropriately apply fermented organic human and animal manure water. Apply 500 kg per mu every half a month to maintain a relatively concentrated fertilizer water, which is conducive to cultivating phytoplankton for photosynthesis and oxygenation, and the fertilizer water is warm. ③ Build a 60-70 square meter frost-proof shed per mu in the deepest part of the pond that is leeward and sunny. Bamboo poles and bamboo strips can be used to clamp grass 3-4 inches thick and 20-30 cm away from the water surface to build a shed to prevent cold. You can also pile up the turf mud prepared in normal times around the pond base, pay attention to the weather broadcast, and light the turf mud to smoke when the cold wave comes, forming a thick smoke area above the pond base to melt the frost water, which is also very effective and reduces the loss of fish from freezing to death.

3. How do tilapia spend the winter in a fish tank?

Tilapia is a tropical fish, an African crucian carp, of the order Perciformes, family Cichlidae (also known as Cichlidae, genus Cichlidae). Don't let the tank freeze when you put it in the house, you can also use a heating rod!