Why Do Koi Jump Out of the water?

You may have just purchased some koi or have kept them for a long time. Either way, you may eventually notice that koi will jump on occasion. But why do they jump?

Why Do Koi Fish Jump Out of The Water?

Koi fish may jump out of the water if they are spooked by predators, dealing with poor water quality, experiencing a new environment, or have parasites. To better understand this behavior and the underlying reasons let’s take a closer look at each. 

Poor Water Quality

First and foremost, if you notice your koi jumping, check the water quality. It’s possible they are jumping in an attempt to escape dirty water. You may also notice them huddled up at the skimmer or waterfall outlet. 

Checking the water quality can be done with any test kit designed for ponds or aquariums. If you do detect high levels of ammonia or an unsafe pH level, perform a water change as soon as possible.  


Grey heron with caught fish in beak

Koi may jump out of the water if they get scared or excited. If they are scared it is likely due to the presence of predators either real or perceived. Large birds and other wild animals will take a koi if given the chance. 

They may also see a fast-moving noisy pet or child as a potential predator and react by jumping. 

In any case, there are a few things you can do to help protect your koi. If you have had predators take fish or are seriously concerned about it, cover the pond. This can be done with a net or by some other means depending upon the type of predator. 

You can also place a koi castle or other fish shelter in the water. This will give them a safe space to hide when frightened.

Drastic Change In Environment

It is fairly common for koi to jump when placed in a new pond or tank. Whether they do this out of excitement or curiosity is hard to say. Regardless of the reason, this behavior usually subsides in 2-3 days.

A net is a good way to prevent any serious mishaps and can be taken off when the jumping subsides. 


Koi fish may also jump if they are experiencing high parasite loads. If this is the case, their primary behavior will be flashing, not jumping. Flashing is when the koi turn on their side and swim erratically, often rubbing against objects. 

If your koi are exhibiting this kind of behavior make sure you get it identified and treated quickly.

How To Stop Koi From Jumping Out of The Pond

While koi jumping may be fun or interesting to watch, it can be fatal. If a koi jumps out of a pond onto land it needs to be put back into the water immediately. If it is out of the water for more than a couple of minutes it will die. Most of us don’t have the luxury of watching our koi ponds all day to prevent this from happening. 

So what can be done to prevent this? First, you need to address the root cause from the reasons listed above. In the meantime, you can install netting over the pond. While this is unattractive, it is effective.