Goldfish generally take 5 to 10 hours to spawn. Goldfish don't release all their eggs at once. Spawning usually starts around 4 a.m. and ends around 10 a.m. The first spawning may take a bit longer, but it generally still finishes within 10 hours.
Factors that affect the spawning time of goldfish include water temperature. The water temperature for goldfish to spawn should be between 10°C and 20°C. If the water temperature is not suitable, goldfish may not spawn. Therefore, properly adjusting the water temperature can stimulate goldfish to spawn. Additionally, goldfish typically spawn in spring. When the water temperature is between 15°C and 25°C, mature parent fish will start to spawn.
To encourage goldfish to spawn, you can put clean water of an appropriate temperature in the spawning tank, and then place male and female goldfish in it. After spawning, the goldfish should be promptly removed to prevent them from eating the eggs.