Third, fry management
After the larvae have left the nest, they begin to feed and gradually shift from endogenous to exogenous nutrition. Therefore, it's crucial to focus on fry management during this stage, ensuring clean water and a steady, sufficient supply of food. Proper care during this period significantly impacts survival rates and healthy development. The feeding process for fry should start once they are fully removed from the nest. Naturally occurring plankton or artificially cultivated microorganisms are ideal as initial feed. Artificial feeds can also be used if necessary. In the first week after swimming, fry can be fed salmon powder up to 6-7 times daily. It's important to start feeding from the edges of the pond and gradually move toward the center. Overfeeding must be avoided, as it can lead to severe water pollution and negatively affect the health and survival of the fry. By the second week, live leeches can be introduced, fed 3-4 times per day. In the third week, as the fry grow, they can be given whole worms depending on their condition. Whenever possible, leeches are recommended, as they play a vital role in promoting the growth of fish fry. Water quality management is equally critical during the fry stage. Maintaining clean and fresh water is essential for their development. Adding probiotics to the hatchery not only improves water quality but also serves as an additional food source for the fry. Water should be added gradually in stages. When the fish are weak, extra care must be taken when changing the water. Sudden changes in water flow, temperature, or other water parameters can stress the fry. If partial water changes are needed, the discharge should be done slowly, and a fine mesh gauze (50 mesh) should be placed over the outlet pipe to prevent fry from being lost. Fourth, fry selection Fry can be sorted when they reach about 1–1.5 cm in length, typically at one month old. The sorting process includes: 1. After several passes with a 50-mesh nylon net, when few fry remain in the pond, drain the water and use water to collect the remaining fry. 2. Avoid using fishing nets for catching fry; instead, use plastic containers or ceramic bowls filled with water to safely transport them. 3. During the first sorting, remove any fry with abnormal tail fins or body deformities, such as single-tailed, fan-tailed, or curled-tail individuals. If breeding for specific varieties, also eliminate those with irregular scales. 4. When the fry grow to 2–3 cm, a second round of selection takes place. This time, focus on removing individuals that do not meet the variety’s standards in terms of size, color, or physical appearance. For high-quality fish breeding, strict selection should occur when the fish reach 5–6 cm. Choose those with elongated bodies, long tails, and strong fin structures. Those that don’t meet the required color or morphological traits should be eliminated. This careful selection ensures the production of healthy, high-quality fish.Calcium Hydroxide,Slaked Lime,Hydrated Lime,Food Grade Calcium Hydroxide
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