The following conditions are required for koi breeding:
Water Quality Conditions: The water quality for koi breeding needs to be clean, slightly alkaline, and of low hardness. The pH value should be between 7.2 and 7.4, and the dissolved oxygen content should be ensured to be above 4mg/L. Koi have relatively strong adaptability to the water quality environment, but they don't adapt well to drastic changes in water temperature. Generally, when changing water or transferring koi to another pond, the temperature difference of the water should not exceed 3 degrees Celsius.
Selection of Parent Fish: The parent fish used for breeding must be in robust health, free from diseases, injuries, and disabilities. They should have bright colors, pure strains, smooth and neat scales, a steady swimming posture, and complete fins without any defects. For male fish, it's best to choose parent fish aged between 3 and 5 years old. Female fish are generally required to be between 4 and 10 years old. Such parent fish are in robust health, with full gonads and strong vitality of eggs and sperm, resulting in high fertilization and hatching rates.
Breeding Methods: Before breeding, it's advisable to raise male and female fish separately and then put them back into the spawning pond when it's time for breeding. Generally, small concrete ponds with an area of about 20 square meters are used as spawning ponds. The breeding water should have a pH value between 7.2 and 7.4, and it's better if the water quality is clean, slightly alkaline, and of low hardness.
Feeding and Management: Koi are omnivorous fish, and they can be fed with either plant-based baits or compound feeds. The stocking density should not be too high. For concrete pond cultivation, it's appropriate to stock 5 to 8 fish per square meter. For pond cultivation, when the fingerling size is 5 to 15 centimeters, the stocking density of 1000 to 1200 fish per mu is advisable. Feeding them in small amounts but more frequently helps koi grow rapidly.
By meeting the above conditions, the breeding and healthy growth of koi can be effectively promoted.