Detailed Explanation of Key Technical Points for Spring Stocking of Tilapia Fry

The whole year's work depends on a good start in spring. After mid-March, air and water temperatures in South China begin to rise gradually and stabilize; farmers are now in the preparation stage for stocking tilapia fry.

1. Precautions for stocking fry

Relevant preparatory work should be done before stocking fry. After the pond is cleared, it is best to dry the pond for a few days and use quicklime for disinfection and sterilization; when drawing water into the pond, pay attention to using fine-mesh screens or net cages to block the inflow of wild trash fish and other debris from outside; follow the principle of “stock fry in shallow water, grow them out in deep water”; generally fill with 80cm~100cm of water before stocking fry, then gradually increase the water depth afterward; prepare a thermometer for air temperature and one for water temperature, and measure the air and water temperatures frequently; only stock the fry when the weather is stable and the water temperature rises above 20°C and will remain stable or continue to rise; 3~5 days before stocking, carry out one insecticidal and bactericidal treatment of the water body, and after the efficacy has dissipated, select a small number of fry for a water test, and only stock according to plan after confirming it is safe.

Selection of tilapia fry: according to different farming environments and farming models, reasonably select tilapia strains suitable for farming (such as the Oreochromis niloticus strain, the GIFT strain, etc.); tilapia fry produced by reputable hatcheries with stable quality should be selected for stocking; be good at observing the fry: the preferred healthy fry are those with strong physiques, no mechanical injuries, and quick swimming, and that can quickly swim competitively in the same direction after the water in a basin is gently stirred by hand.

Try to avoid causing mechanical injuries during handling, and do a good job of sterilization and disinfection during packaging and transportation. After the fry arrive at the pond, pay attention to equalizing the temperature before releasing them into the pond, and try to avoid stress.

2. Farming management recommendations

1. Conduct frequent sampling inspections and pay attention to killing pests such as Trichodina, Chilodonella, and Gyrodactylus, following the principle of killing insects first and then sterilizing, to avoid the breeding of pests and saprolegniasis pathogens that harm tilapia seedlings.

2. Pay attention to water quality regulation and keep the water quality “fresh, tender, and smooth.”

Use quicklime or “enzyme bacteria” microbial preparations to regulate and maintain water quality; pay attention to testing the pH value, nitrite, and ammonia nitrogen content in the water body, and carry out degradation and regulation work in a timely manner; reasonably supplement base fertilizer to balance the reproduction of beneficial algae and bacteria in the water body; as the fry grow, gradually add new water.

Feed reasonably to ensure the healthy growth of fry and improve the survival rate of seedlings. At the fry stage, choose high-protein, high-quality powdered feed as the main bait; based on small amounts and more frequent meals, feed at fixed times, with fixed quality, and in fixed quantities according to proportions; generally, at the fry stage, a feeding ground position at a relatively long distance should be chosen to ensure that the fry feed evenly and grow at an average rate; timely and appropriately add antibacterial, liver-protecting, and health-care drugs to the feed to further improve the disease resistance and immunity of the fry.

Pay attention to driving away and clearing snakes, birds, frogs, and other organisms to avoid these fish natural enemies preying on tilapia fry and to reduce seedling losses.

Pay close attention to weather conditions and carry out relevant farming management work according to actual conditions.