goldfish reach sexual maturity and can reproduce when they are about one year old. Some fast-growing goldfish can reproduce when they are 7-8 months old. If the water temperature rises properly in winter, they may enter the breeding period ahead of time. Normally, this kind of fish does not lay eggs only once in each breeding period, but lays eggs 3-4 times at a time.

The breeding period of goldfish is generally in the transition between spring and summer, probably between March and June, and April-June is the best breeding period of goldfish, at which time goldfish will lay eggs about once a week or two. Eggs will hatch small fish 3-7 days after fertilization. The best water temperature for this fish during breeding period is 18-25 ℃.

Normal goldfish can lay 5000 eggs at a time. But the number of goldfish breeding is mostly different. The number of eggs laid by different varieties and individuals is different. The number of eggs laid by the same fish several times during reproduction is also different. Healthy fish can lay thousands of eggs at a time. This kind of fish normally has the largest number of eggs during the second spawning period, and the first and last spawning are the least. Weak, old and malnourished fish will lay fewer eggs. Sexually mature females usually lay eggs 2 ~ 3 times, even 4 ~ 6 times. There will be a period of time between each spawning, which is about 10 days.