Temperature increases are the most common way to stimulate mating as they signal the start of spring or summer. Heavy water changes (50% or more) also mimics the rainy season for seasonal fish, especially Amazonian and African species that wait for the flood season to breed.

What is the mating season for fish?

Most fish species are stimulated to breed in the springtime when the water warms up and the daylight lengthens. You can replicate this anytime in your home aquarium by doing water changes, increasing the temperature setting on the aquarium thermometer, and gradually increasing the length of time the lights are on.

How do I know if my fish are mating?

Mating Ritual

Signs that your goldfish are ready to mate include white spots along the gills of the males, and the female will become fatter and more rounded. The male will then chase the female around the tank to encourage her to release her eggs.