What Time of Year Do Koi Spawn?

Koi fish are one of the most popular and beautiful species of fish that people keep in their ponds. Apart from their stunning colors and patterns, koi fish are also known for their breeding habits.

Breeding koi fish can be quite an exciting and rewarding experience for many pond owners. However, to breed koi fish successfully, it is important to know when they spawn.

What is Koi Fish Spawning?

Spawning is the process of reproducing or laying eggs by female koi fish, which are then fertilized by male koi fish. The fertilized eggs hatch into fry, which eventually develop into adult koi.

When Do Koi Spawn?

Koi spawning season usually takes place during the spring and summer months when the water temperature begins to warm up. In most cases, koi spawning season begins when the water temperature reaches about 68°F (20°C) and continues until it reaches around 75°F (24°C).

Factors That Influence Koi Spawning

Several factors can influence when koi fish spawn. Here are some of them:

Water Temperature

As already mentioned, water temperature plays a crucial role in determining when koi start spawning. When the water temperature rises above 68°F (20°C), the females begin to produce eggs, and males start to chase them around.


The nutrition level of your koi fish can also affect their spawning habits. A well-fed female will produce more eggs than a poorly fed female.


Age is another factor that affects koi spawning habits. Typically, younger females will lay fewer eggs than older females because they have not yet fully developed.

Koi Spawning Behavior

During breeding season, male koi become more aggressive and territorial while females develop rounder bellies full of eggs. The male koi will chase the females around the pond, nudging and bumping into them to stimulate egg release. Once the female releases her eggs, the male fertilizes them by spraying milt over them.

How to Encourage Koi Spawning

If you want to encourage your koi fish to spawn, you should pay attention to water quality and make sure that it is suitable for breeding. You can also increase the water temperature by using a heater or adding more sunlight exposure.


Spawning is an exciting and fascinating process in koi fish breeding. Knowing when koi spawn is essential if you want to breed your own koi successfully. By paying attention to factors like water temperature, nutrition, and age, you can encourage your koi fish to spawn and enjoy watching this beautiful process unfold before your eyes.

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Daniel Bennet