ZHONGSHAN G.H.L. TRADING CO., LTD. , https://www.ghltrade.com
Breeding techniques of carp seedlings
Whether carp pond aquaculture can achieve good economic returns largely depends on the seedling cultivation phase. This stage is critical, as it sets the foundation for healthy growth and productivity.
1. **Seed Acquisition**
Fertilized eggs are purchased from Heilongjiang and hatched in-house. The fertilized eggs have a diameter of about 2 mm and are kept submerged. The water temperature is maintained between 19.5°C and 20.6°C. After approximately 80 to 120 hours, all larvae hatch, with an average hatching rate of 80%. During this process, there is a time lag between when the first larvae emerge from the egg membrane and the rest. Therefore, as soon as the first fry appear, we collect them in batches to ensure optimal survival rates.
2. **Seedling Cultivation**
**Stage 1:** Newly hatched larvae are placed in micro-flowing water on hatching trays. The stocking density is around 6,000 per square meter. At this early stage, the fry do not yet feed, so they rely entirely on their yolk sac for nutrition. Oxygen levels must be carefully monitored and maintained throughout. Daily operations require careful handling to avoid stress or damage to the fragile fry. After 4 to 5 days, when the yolk sac is absorbed by two-thirds, feeding can begin.
Due to the sensitivity of the fry during this domestication phase, many die. To address this issue, I prepared specialized powdered feeds for stages S1, S2, and S3 (with crude protein content above 45%), combined with live Artemia and water fleas (without worms). This combination significantly improved survival and growth. Within half a month, the feeding rate reached 45%, and the fry grew to about 3 cm in length, at which point they were transitioned to feed S3.
**Stage 2:** Fry larger than 3 cm are moved to a cultivation pond. The pond is designed with three layers: 3 meters, 1 meter, and 0.5 meters deep. The top layer is filled with water, and the drainage hole is controlled via an overflow pipe. The pond is covered to protect the fry from direct sunlight, heavy rain, and other environmental hazards.
Feeding is done according to 25% to 45% of the fish’s body weight, divided into 8 small meals per day. Before each feeding, the system is cleaned, and both air and water flow are temporarily stopped to ensure optimal digestion and reduce waste.
**Stage 3:** When the fry grow beyond 10 cm, they are transferred to a larger pool measuring 6 meters by 4 meters. Before moving the fish, the cement pool is disinfected using a 20 ppm potassium permanganate solution, scrubbed clean, and then rinsed thoroughly. The fish are dipped in a 10 ppm dimethicone solution for 3 to 4 minutes before being introduced into the new environment. Once the fish reach a size of 25 cm or more, and weigh between 50 to 100 grams, they are considered ready for breeding. At this point, the breeding phase is deemed successful, and the fish can be safely used for further production.