Hezhuang is a remarkable example of goldfish breeding, known for its elegant appearance and vibrant energy. Its sleek, silver-white scales shimmer under the light, while a striking red "sac" on its head adds a bold contrast. This combination of colors creates a visually appealing display, and its graceful movements resemble the gentle flight of cranes.
**1. Artificial Breeding**
**1.1 Broodstock Rearing**
The breeding process begins in March each year. Female fish selected are typically 2–3 years old, while males are 1–2 years old, with a recommended ratio of 1:1.2. The broodstock should have a well-defined red sac on the top of their heads, as irregularities such as yellow or white spots are generally avoided. Stocking density is kept lower than for commercial fish, and feeding increases gradually as temperatures rise. It usually takes about one month for the gonads to mature.
**1.2 Selection of Broodstock**
In early April, breeders examine the gonads of the fish. Females should have a soft, elastic belly and an oval shape, while males should be strong, with full, flared fins. These characteristics help ensure high-quality parent stock.
**1.3 Artificial Spawning**
Artificial oxytocin is commonly used around mid-April when the water temperature reaches 25°C. A disposable pectoral fin injection method is applied. For every 100g of female, 1–2μg of LRH-A2 is injected, while males receive half that amount. The best time for injection is around midnight, and the fish are left to rest for 18–20 hours.
**1.4 Artificial Insemination and Incubation**
At night, once males are observed chasing females intensely, both are quickly transferred into a container filled with water. When females show signs of releasing eggs—such as milky white mucus or yellow eggs—they are ready for artificial insemination. One person gently presses the female’s abdomen to release the eggs into a sterile basin containing warm saline. Males are then squeezed similarly, and their sperm is mixed with the eggs using a feather. The fertilized eggs are then placed in a hatchery.
During incubation, clean, oxygen-rich water with a pH of 7.5–8.0 is essential. At 25°C, the eggs hatch within 3–4 days. To prevent fungal infections, a 10ppm malachite green solution is added daily, and fresh water is maintained regularly.
**2. Seed Cultivation**
Newly hatched larvae rely on their yolk sac for nutrition. Four days later, they begin feeding on crushed cooked eggs, which are suspended in water using 25# plankton nets. They are fed once daily, with the amount adjusted so that food is consumed within 1–1.5 hours. By day 8, the larvae grow to about 1 cm, showing improved swimming ability and beginning to eat small plankton. As they grow to 3 cm, water changes are done weekly, and they are introduced to larval feed.
**3. Discussion**
**3.1 Advantages of Artificial Insemination**
Artificial insemination significantly reduces the physical stress on broodstock during the mating process, which can last up to 10 hours. This leads to fewer deaths and higher survival rates—up from 50%–75% in natural mating to over 95% with artificial methods. Fertilization rates also improve, rising from less than 40% naturally to over 80% with artificial techniques. Additionally, it ensures the purity of the species.
**3.2 Precautions**
Fish nests should be suspended in the upper layers of the water, with weights attached to keep them stable. If they float to the surface, the eggs may be exposed to sunlight, leading to suffocation if they sink to the bottom. During the critical first three days of incubation, the eggs must not be moved, as this can reduce hatching success and increase the risk of deformed offspring.
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