The optimal stocking density for goldfish breeding depends on multiple factors, including the size of the fish tank, the varieties and ages of the goldfish, etc.
The Relationship between the Size of the Fish Tank and the Number of Goldfish: Generally, each one-year-old goldfish needs about 10 liters of water. For example, an aquarium that is 80 centimeters long, 40 centimeters wide and 40 centimeters high has a volume of 128 liters and can accommodate 12 one-year-old goldfish. If the density is too high, it will be difficult to maintain good water quality, and goldfish are likely to fall ill, die or suffer from lack of oxygen.
The Requirements of Different Goldfish Varieties for Density: Different varieties of goldfish have different requirements for density. For instance, the stocking densities for precious varieties like Pearlscale, Butterfly Tail and Bubble Eye should be lower because these varieties are more sensitive to environmental changes.
Water Quality Management: Maintaining good water quality is the key to ensuring the health of goldfish. The ideal ratio of fish to water is 1,000:1, which means there should not be more than one goldfish per liter of water. Besides, the ratio of the body length of goldfish to the length of the fish tank should be above 1:10 to ensure good water quality and sufficient dissolved oxygen. If the breeding density is too high, the water quality will deteriorate rapidly, there will be a shortage of dissolved oxygen, and goldfish will be prone to getting sick, dying or dying from lack of oxygen.
Other Management Measures: Besides controlling the density, measures such as regularly cleaning the fish tank, appropriately increasing oxygen supply and avoiding overfeeding also help to keep goldfish healthy.