Koi jumping out of the water can be really cool to see. However, it’s definitely not always a good thing. When a koi jumps out of the water, it runs the risk of hurting itself on the water surface, plants, or the rocks at the edge of your pond. Butterfly koi are especially susceptible to injury like this to their fins. The fish even run the risk of beaching themselves outside of the water, which can be fatal. That being said, jumping koi isn’t always a bad thing by any means. Often, it just depends on why your koi happen to be jumping. There are three main reasons why your koi might be jumping.
1. Jumping is fun
This is the main reason why koi jump. Many animals, fish included, simply enjoy jumping. If your fish are particularly jump-for-joy-inclined, there really isn’t much that you can do about it, other than trying to minimize the damage that they can do to themselves (though koi that are jumping for pleasure are far less likely to injure themselves). Carefully placed netting can help with this. Otherwise, enjoy. It’s adorable.
2. They’re exploring
This jumping behavior is most often seen by koi that are new to their environment. Koi are fairly smart fish, and as such they like to know their surroundings. Part of this involves exploring the outer limits of their pond. You’ll most often see new koi jumping at the waterfall or skimmer areas. Temporary netting can prevent injury with new fish, and keeping an eye on new fish for a while after introducing them to a new pond is a good idea for many reasons, jumping behavior included. Your koi might also start back with the aerial exploration in spring or after major changes to their environment (such as new plants or waterfalls). The last reason why they might go exploring a pond that’s already familiar is because they’re hungry. Try feeding them a bit more.
3. They’re uncomfortable in the water
This is the jumping behavior that you really can, and should, do something about. If something in your pond levels is wrong enough, your fish might go looking for a way out. Grab a test kit and try to figure out what’s wrong. If your pond composition is fine, it could also be fear of predators. Make sure that your pond has enough space for your koi to hide from time to time, or they’ll be uncomfortable in the water and may look to escape, and if you’re building a new pond, keep in mind that koi love deeper water that lets them hide from predators. Sometimes koi also get uncomfortable in unusually warm pond water in the heat of summer and jump. This is especially common in shallower ponds in full sun in the South. Adding a bit of shade to some of your pond might be a good idea, and, again, giving your koi somewhere to hide from the sun while in the pond is a good idea. Finally, koi sometimes get uncomfortable and jump because of an overcrowded pond. Always make sure that you have more room than you need when adding new fish to your pond.