Whether you have fish in your ponds or not, oxygen is the most important element of a pond. Water with insufficient oxygen levels is unhealthy for the plants and fish in the ponds. So, many pond owners overcompensate by adding too much aeration.

This is where things go wrong. Excessive aeration may result in the pond having more oxygen than necessary.  Too much oxygen in a pond will not only result in the pond looking murky,  but it will also kill the fish in the pond.

Let’s take a look at how a pond can have too much oxygen and what to do to prevent it.

How can a pond have excess oxygen?

You may have a vague idea about how there can be too much oxygen in the pond water. Let’s make one thing clear, if the pond is being oxygenated through natural means, it can’t have excess oxygen.

Because there is barely enough oxygen in the air as it is, the atmosphere can’t supply excessive oxygen anywhere in the world. So, if your pond gets too much oxygen, then it surely is from the various machines and devices that are installed in your pond.

Can A Pond Have Too Much Oxygen

Pond pumps

As pond pumps are the main artificial source of oxygen, they are also the main cause of excessive oxygen. Usually, the pumps are anything but a source of headache for the pond owners. But, the problem arises when the pump installed is too big for the pond.

If the pump moves too much water concerning the size of the pond, the production of oxygen will be too much. The pond water will then become murky and unhealthy for the inhabitants of the pond.


Another source of excess oxygen is the aerators. As aerators supply air to the pond water, they always run the risk of disturbing the water too much. If the aerator is too powerful for the size of the pond, the water will be disturbed and too much oxygen will be produced.

Air Compressor/Pump


Air Compressors are another device used to oxygenate the pond. They move water through various pipes, so the water pressure is a bit higher than most other circulating devices.

So, if you install a more powerful compressor than you need, excessive oxygen will be produced which will not only harm the fish but also ruin the whole ecosystem of the pond.


These are a version of aerator devices that provide air into the pond. An air compressor is installed on the bank of the pond which provides air to diffusers that are in the pond through hose pipes. Usually, you need only one diffuser per pound.

But if you install more than one diffuser in a pond that is too small to do so, you will have a pond that contains more oxygen than necessary.

How do you know there is too much oxygen in your pond?

There are oxygen level readers available in the market using which you can measure the oxygen levels in your pond. You can measure the total dissolved gases (TDG) in your pond. A high level of TDG will mean you have too much oxygen and/or nitrogen in your pond, both of which are harmful if taken in excessive amounts.

Also, oxygen levels in terms of ppm (parts per million) are another way of finding out if there is too much oxygen in your pond. The ideal level of oxygen in a pond is 5-10 ppm. If you find out that the oxygen level is above 10 ppm, it will mean the oxygen is way above the ideal level it should have been.

Things to consider while measuring oxygen levels

While measuring the oxygen levels, keep in mind that various things like water temperature and the depth of the pond can affect water temperature.

Coldwater is more oxygenated than warm water. As cold water is heavier than warm water, it stays at the bottom of the pond while the warm water is on the surface. So, make sure to measure the oxygen levels of both the top and the bottom of the pond waters to get a full picture of the overall water level of the pond.

Also, as days are warmer, the water will be warmer during the day. To know the actual oxygen levels, test the water during various points of time of the day.

Deep ponds will contain more oxygen than shallow ponds. Because the water in the deeper ponds will take more time to warm up than the shallow ponds which can get warmed up pretty fast.

How can excessive oxygen harm the pond?

Excessive oxygen can adversely affect the pond in two main ways. It can affect the health of the fish and it can affect the pond’s environment.

Effect on fish health

The effect excessive oxygen has on fish is quite lethal. Too much oxygen causes the Gas Bubble Disease for them. The main symptoms of this disease are

  • Loss of equilibrium
  • Unnatural floating near the surface
  • Uncontrollable head shaking
  • Convulsions
  • Flared up Opercula
  • Discharging an unnatural amount of gas through the buccal cavity
  • Blindness
  • Hemorrhage of various organs such as gills, muscles, fins, etc.
  • Dying with their mouths open

Effect on pond environment

Too much oxygen leaves your pond murky and cloudy. Sunlight can not properly enter the pond through this cloud of sediment, resulting in the death of the pond plants. These dead plants will sink to the bottom and create sludge,  and you will have a whole new problem in your hands.

How to properly oxygenate the pond?

To make sure your pond is properly oxygenated, that is the oxygen level is neither too low nor too high, you have to install proper devices in it. Install pond pumps and aerators that will facilitate oxygen production, but make sure you have the right-sized device installed in them.

If the device is not powerful enough for the pond, you will have insufficient oxygen. On the other hand, a device too powerful will produce more oxygen than necessary.


As we know, excess of anything is bad. No matter how useful a thing may be, there is a limit to how much it should be produced and used. Oxygen is not any exception to this rule at all. I hope you understand after reading this article that a pond can’t have too much oxygen, it’ll work against the interests of the pond.

So, install proper devices with proper measurements to keep the pond and the fish healthy and thriving.

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