Do Koi Fish Need Oxygen? & Do Koi Need Oxygen Air Pump?

Koi fish are colorful and eye-catching but require extra care and knowledge to preserve. One of the hardest aspects to take care of is the pond’s environment.

We all know that koi fish need oxygen to survive and thrive. That’s why oxygenation is an important factor affecting the creatures’ living environment.

This post will provide you with helpful knowledge related to the koi fish oxygenation topic, so stay tuned to know how to care for your pets better.

How Long Can A Koi Fish Survive Without Oxygen?

The length of time that koi fish can live without an adequate oxygen supply may be from a few hours to a few days. But if there’s no dissolved oxygen present in your pond, they’ll obviously die within a few minutes.

As long as there is 5-6 ppm (parts per million) of properly dissolved oxygen in the pond, your pets should be fine for a few hours at least until you apply one or multiple oxygenation methods that provide the tank with adequate oxygen.

What Affects Koi Pond Oxygen Levels?

Salinity, water movement, water temperature, and the pond’s precise oxygen levels are the primary factors that affect the particular amount of time that your Koi can live without properly dissolved oxygen.


Salinity is a measure of the dissolved salt content in water. While freshwater typically has a salinity of less than 0.5%, seawater has a salinity of around 3.5%.

Even small changes in the salinity of water can have a big impact on oxygen levels. In general, oxygen dissolves more easily in freshwater than in salt water.

As the salinity of water increases, the amount of dissolved oxygen decreases. In fact, one of the biggest challenges for aquarist is maintaining adequate oxygen levels in high-salinity environments.

One way to combat this problem is to circulate the water using aeration devices. By introducing oxygen into the water, it is possible to maintain livable conditions for fish even in very salty environments.

Water Temperature & Movement

Tank temperature has a significant impact on the oxygen levels, yet the degree of aeration and water movement also play a large role.

The general rule is that the warmer the living environment (water temperatures increase), the less dissolved oxygen level it can hold. Why? Because water with lower temperatures has denser water molecules packed closely together.

That means it will be harder for O2 molecules to get away from the water. An environment above 29°C can hold about 6-7 ppm of O2, though it depends on various factors.

Meanwhile, environments of 21°C (70°F) can contain 8-9 ppm of O2. We can see that temperature acts as a massive influencer.

Besides, moving water provides the animals with more surface space to swim than water standing still, hence increasing the level of oxygen.

That’s particularly true when the water moves or splashes over an object (for example, a rock), where it can pick up some O2 molecules and bring them into the tank.

The elevation is also an important factor. If you live in an area at a high altitude, the air pressure and the oxygen level in the water will be low since there’s less force crucial for holding/pressing the O2.

Long-Term Oxygenation Methods For Koi Fish

Air Pumps (Air Compressors)

Fish breeders should know that an air pump is a necessary tool for providing oxygen in the long term.

This tool uses an in-land device with tubing transporting air to a diffusion plate underwater but in another area of your pond (typically the bottom), helping air bubbles distribute to the entire pond.

Air pumps are powerful, suiting perfectly large-sized ponds or those heavily packed with various fish species which consequently require a more meticulous oxygen supply.

Waterfalls & Fountains

Water movement can increase oxygen supply by captivating air molecules when the water moves and boosting the tank surface.

Waterfalls, fountains, or letting a small stream run into your fish pond are excellent methods to continually provide your pets with oxygen.

Submerged plants

Adding plants to your tank or pond is a wonderful natural method to filter any pollutants and excess nutrients water and provide dissolved oxygen.

Submerged plants also offer habitat and shelter for your creatures and other residents, such as frogs and turtles. Also, they can serve as green food sources for the animals.

Decreasing Water Temperature

An intelligent way to reduce the temperature and maintain a good oxygen level is to shade your pond.

It’s not necessary to shade the entire pond. Instead, you should shade a small portion, usually 40%, so that there is still adequate sunlight for various microorganisms, any amphibians and reptiles present, and plants.

The shaded area will have a lower temperature, so it can contain more oxygen.

Short-Term Oxygenation Methods For Koi Fish

Temporary Aeration & Water Changes

If you intend to transport your fish to quarantine or stock tanks, you should let them be there just until they’ve recovered from illness or injury or are long and firm enough to move to the next location.

Hence, you can mix more O2 into the tank simply by having a small household fan blow on the water or performing periodic water changes while adding an air pump (bubbler).

Check this video out for more koi pond water change and maintenance tips:

Koi Pond Oxygen Tablets

You can also use oxygen tablets for your pond or temporary tanks. However, this method should be the last resort you think of when it comes to oxygenation.

These tablets contain multiple sodium compounds and hydrogen peroxide that create bubbles while dissolving in water.

The sad news is that those compounds can kill beneficial bacteria, bleach plants, and fish eggs, burn gills and fish scales, and adversely affect water quality.

Tips To Maintain Oxygen Sufficiency In A Koi Pond

Besides the most important tactics above, you need to note these tips down to increase the oxygen supply further. Though they don’t themselves add more oxygen to the pond, they will decrease oxygen depletion.

First, it is important to avoid overstocking the pond. More fish means more waste, which can lead to lower oxygen levels.

Second, strive to minimize the use of chemicals and fertilizers, like herbicides, as much as possible.

Avoid letting them be near your tanks and pond since they can leak into your aquarium and destroy favorable tank parameters, like pH, which may consequently mess with dissolved oxygen concentration.

Since fertilizers will help foster the development of adversely harmful bacteria and algae, they may deplete oxygen.


How long can Koi fish live without a pump?

As mentioned above, without a pump (may be due to pond power outage), the water in the pond will quickly become polluted, and the koi will become stressed and unhealthy.

A pump is an essential part of most filtration systems, as it helps to circulate the water and keep the filter working properly. As a result, koi fish typically cannot survive for more than a few days without a pump.

If your Koi is gasping at the surface of the water or leaning to one side, it may be suffering from a lack of oxygen.

Low oxygen levels can be caused by a number of factors, including warmer water temperatures, overstocking, and poor water circulation. In addition to gasping and listing, other signs of low oxygen levels include lethargy, lack of appetite, and increased aggression.

Do Koi fish need light at night?

In fact, Koi require sunlight in order to synthesize vitamin D3, which is essential for their growth and development. Without enough vitamin D3, Koi can become sick and even die.

For this reason, it’s important to provide Koi with access to natural sunlight or artificial light during the daytime hours.

At night, however, Koi do not need light, and in fact, too much light can disturb their sleep patterns and cause stress. So if you’re wondering whether your Koi need light at night, the answer is no – darkness is just fine for these fish.


The stunning appearance of Koi fish is a great attraction, but remember that it takes a lot of work to protect your pets and keep them happy and healthy.

Koi fish need oxygen and could survive no more than a few days maximum without a proper, active O2 supply.

We hope our Koi oxygenation guide is useful and can help you maintain a thriving Koi pond. Thank you for reading!