How to Increase Oxygen in Your Fish Tank

We are all too familiar with the problems that arise when our fish tanks are deprived of oxygen. Not only does it leave the fish gasping for air, but it can also cause brown algae to grow. Over time, this can create anoxic conditions in your tank, which can be deadly for your fish.

Suffice to say, it’s important to do everything you can to keep healthy amounts of oxygen in your tank and to know what to do in the event of an oxygen crisis. In this article, we will discuss thirteen ways to increase oxygen in your fish tank.

What are the signs of low oxygen level?

Before getting into ways to increase oxygen in your fish tank, it is important to be able to identify when there is a problem. Some common signs that your tank is low on oxygen include:

  • Fish gulping air at the surface.
  • Lethargy of the fish and/or lack of appetite.
  • An increase in the proliferation of brown algae
  • Bubbles in the corner of the fish tank due to water return.
  • Condensation on the aquarium walls (condensation is a good sign of high humidity and low oxygen levels).

In general, mild cases of oxygen deprivation do not cause the signs mentioned above. If your tank is showing these signs, it’s important to get your oxygen levels up as soon as possible. This article will first cover what to do in the event of an oxygen crisis, before delving into the various ways to increase the oxygen in your tank.

Ways to Increase Oxygen in Your Tank in an Emergency

If you suspect your fish tank is low on oxygen, you need to take action immediately. The first thing to do is check the oxygen level in your tank with a good quality fluid test kit. If the oxygen level is below 6 ppm, you may need to take emergency action to increase the oxygen level. Doing it in a timely and effective manner can be the difference between life and death for your fish.

The following are some ways to increase the oxygen in your tank in emergency situations:

Pouring water from a certain height:

This is one of the oldest tricks in the book, and it still works! Pouring water from a height into your tank will create bubbles and increase the oxygen level. Make sure to pour the water directly into the center of the tank so that it is evenly distributed. The movement of the water from the bubbles will also be beneficial.

A good way to do this is to use a pitcher or bottles of water. If you have a garden hose, you can also pour water from the hose into the tank for an instant oxygen boost. Just be careful not to blow your fish up with the high pressure current, as this will likely cause more harm than good!

In addition, you should also dechlorinate the water and make sure the pH levels are in the proper range, as you will be doing these steps with whatever tap water you have on hand. We recommend using a water dechlorinator. You can also use specially formulated aquarium water from your local fish store to increase the oxygen in your tank, if you don’t have a dechlorinator on hand.

big water change

Excessive buildup of debris can decrease the oxygen-carrying capacity of your aquarium water. This is because the accumulation of debris reduces the surface area of ​​the water that is exposed to the air. One way to solve this problem is to do a large-scale water change using oxygen-rich freshwater.

Although we do not usually recommend large water changes, they are necessary in the event of an emergency intervention. To effectively increase the oxygen concentration in your tank, you will need to do at least a 30% water change. You will need to use non-chlorinated tap water for this purpose.

While doing the water change, be sure not to disturb the gravel bed, as this can cause cloudiness that lowers oxygen levels. Finally, make sure not to add any more fish or plants while doing this. If you do, your oxygen levels will drop even lower than they already are.

use ice cubes

Cold water generally has a higher oxygen content, so if you’re desperate for a quick oxygen boost, lowering the temperature can help. To do this, you can put ice cubes in ziplock bags and float them in your tank. This can raise the oxygen level by up to 4 ppm.

It is important that you do not add the ice cubes directly to your tank as this can cause dangerous fluctuations in the water. You also run the risk of introducing impurities and bacteria into your tank with the ice cubes as it melts. Using the ziplock bag method allows you to gradually lower the temperature of the water without these drawbacks.

Another thing to keep in mind is staying within your fish’s preferred temperature range. For example, if your fish prefer temperatures between 70 and 78 degrees Fahrenheit, look for something on the cooler end of that spectrum. Colder water can raise oxygen levels, but can also be harmful or deadly to fish if the temperature is too low.

Use a battery powered air pump

Air pumps are a must for aquariums in general, so it can be strange to find this recommendation in emergency advice. However, battery-powered air pumps can be a boon if your oxygen emergency is caused by a power outage. Electric powered air pumps will not work in the event of a power outage, but battery powered pumps will continue to work normally.

If you have an extra battery, or if you can borrow one from a friend, this can be a lifesaver. Keep in mind that the pump will only last as long as the battery lasts, so it’s important to have a plan to recharge or replace the battery.

Because these types of air pumps tend to be smaller and more portable, they can result in a weaker water flow than the typical electric air pump. If this is the case, you may need to use more than one pump to sufficiently oxygenate your tank.

Ways to increase oxygen in the fish tank (permanent solutions)

Now that we’ve covered the temporary measures to take in the event of a sudden or short-term oxygen depletion, let’s move on to some permanent solutions you can put in place for the long term. These solutions will maintain a healthy level of oxygen in your tank without you having to worry about it!

Use a kitchen strainer

A Hang-On Back (HOB) filter is a popular option for fish tanks as it is easy to use and does not take up a lot of space. In addition, these types of aquarium filters work very well as oxygenators. They work by drawing water into the filter and processing it before releasing it through the filter outlet. This creates turbulence in the water, which increases the amount of oxygen contained in the filtered water.

Another benefit of using a ceramic filter is that it helps maintain water quality. This is important because lower water parameters can lead to decreased oxygen levels. So a HOB filter will not only help increase oxygen levels, it will also work to keep your tank healthy overall.

Although a HOB filter can do wonders for the oxygen levels in your tank, it is known to be one of the least powerful filter types. Aquarists with larger tanks may prefer strong filter types, such as a canister filter. Unfortunately, the filter outlet of these types of filters is usually below the surface of the water, making it difficult to aerate the tank through agitation of the water surface. Fortunately, the next entry on our list provides a solution.

Use a spray bar

A spray bar is typically used in conjunction with cartridge filters. This works by allowing water to hit the surface of your tank before it returns to your filtration system. This creates turbulence in the water which, as we know, increases the oxygen-carrying capacity of the water.

When using a spray bar in conjunction with a cartridge filter, it is important to first install the spray bar in the outlet pipe leading to your filtration system. After this, simply position the spray bar at an angle such that it faces the side of your tank. This will create a gentle waterfall effect that disperses oxygen-rich water throughout the tank.

Although a spray bar is a great way to supply most tanks with enough oxygen, it can be less effective in tanks that are wider than they are deep. In these cases, it is best to use multiple spray bars to achieve the desired level of oxygenation.

Use fountain heads

The following tip is so much fun! Fountain heads create a stunning visual effect in your tank while increasing oxygen levels. Like spray bars, fountain heads work by agitating the surface of the water, increasing the amount of oxygen that dissolves into it.

There are a variety of fountains to choose from, so it’s important to find one that suits your tank’s specific size and decor. We recommend opting for one that has an adjustable flow rate. This will allow you to control the flow of water to minimize any negative effects strong currents may have on your fish.

Although fountain heads are very easy to install, they can cause a bit of a mess due to all the water droplets they produce. Therefore, these are best for tanks or ponds with a larger surface area of ​​standing water. They are a great alternative to spray bars!

use air pump

We have discussed the use of battery powered air pumps in oxygen emergencies, but any type of aquarium air pump can also be used on a regular basis to increase oxygen levels. This is because air pumps create air bubbles that rise to the top of the tank and disperse oxygen into the surrounding water.

To use an air pump effectively as an oxygenator, it is important to place it in a location where the bubbles have enough time to reach the surface of the water. This will maximize the exchange of oxygen between the water and the air bubbles. Nothing deprives your tank of oxygen like a lack of water movement, so air pumps are very helpful in this regard.

The downside to using an aquarium air pump is that it can be quite noisy. If this is something that bothers you, you may want to consider placing your air pump in a different spot from where you sit when you watch TV or work on your computer. Or, if silence isn’t important to you, you can always consider using an electrically powered water pump.

wave maker

Another way to increase oxygen levels in your tank is by using a wave generator. Wave generators break the surface tension of the water, which helps the water circulate. This in turn increases its oxygen content because as the waves move across the surface of the tank, the wave generator brings fresh air into contact with the water, allowing gas exchange to occur.

Wavemakers are available in electronic and mechanical varieties. While both work well for increasing oxygen levels, we recommend using a wave generator that runs primarily on electricity rather than one that uses a battery because they tend to be more energy efficient and quieter than battery-powered models. Also, make sure you position your wave generator correctly! You want to maximize the benefits you provide, and this is one of the best ways to do it.

One great feature of wave generators is that you can use them to create various speeds of water flow throughout the day to suit the different needs of your fish. This is a great feature because it eliminates the need to use multiple devices to achieve the desired level of oxygenation.

Fueling your tank correctly

Overfilled tanks are another cause of low oxygen levels. When there are too many fish in a tank, they use up the available oxygen much faster than they would if fewer fish were present. Naturally, this causes the oxygen concentration in freshwater tanks to plummet.

When you fill your tank, just add as many fish as you can comfortably fit on its surface. Another helpful tip is to include more non-fish inhabitants, such as plants, in your tank to provide a more natural environment for your fish and reduce the amount of competition for oxygen.

If a lack of oxygen is still a problem in your tank even after you’ve taken these tips into account, you may need to consider moving your fish to larger tanks that can accommodate their increased oxygen needs. This will prevent you from having to deal with further health issues caused by a lack of oxygen in the tank.

taking care of your plants

Aquarium plants are important for increasing oxygen levels in a tank because they draw carbon dioxide from the water and release oxygen. This form of gas exchange not only provides fish with a more natural environment to live in, but also plays an important role in maintaining oxygen levels.

To help you and your fish enjoy the benefits of plants, we recommend using live plants for beginners that will quickly fill the tank and create a thicker canopy. Carpet plants like Java Moss and Dwarf Hairgrass are great choices because they grow very quickly to create a stunning visual effect in your tank.

In addition to selecting the right plants to stock your tank, you also need to care for them properly. To give your plants the best chance of thriving in a tank, provide them with proper lighting and keep all of your plants well-fed with the proper aquatic plant food. Even quiet species like Anubias plants will benefit from the extra care.

Control of temperature increases

Having elevated water temperature in your tank is bad news for both your fish and oxygen levels. Warm tank water not only makes it hard for fish to breathe, it also encourages the growth of harmful bacteria that can quickly deplete the available oxygen in a tank.

One way to combat temperature rises is to install a chiller unit in your aquarium system. Chiller units work by using a refrigerant to lower the temperature of the water, which in turn reduces the need for oxygen. If you live in a hot climate or your tank tends to get hot, installing a chiller unit can be a great way to ensure your fish always have enough oxygen in the water.

Of course, this is not to say that you should only house your fish in cold water. Different species of fish thrive in different water temperatures, so it’s important to research the ideal temperature range for each of your fish before making a purchase.

Beware of chemicals and medications

We always advocate chemicals and medications as a last resort after all other options have been exhausted. If used effectively, chemicals and drugs can be a quick and effective solution to death and disease, but if used improperly, they can be very harmful.

One of the most important things to keep in mind when using chemicals or medications is that they tend to reduce the oxygen content of your tank water. When you are medicating your fish, always make sure there is plenty of oxygen available in the water and monitor oxygen levels closely. If you notice a significant drop in oxygen levels, discontinue use of the medication and take steps to increase oxygen levels immediately.

Chemicals can also come from your water supply. For example, tap water is often chlorinated, which can be very harmful to fish. To provide your fish with fresh, chlorine-free water, we recommend testing the water from an unknown source before adding it to your tank. You can also use a water conditioner like Prime to remove chlorine and other harmful chemicals from the water.


Nothing is worse than finding a tank without oxygen on your hands, so take steps to prevent this from happening in the first place. By following our simple guidelines, you can ensure your fish have enough oxygen available to breathe and thrive in your home!

Did you enjoy this article? If he did, please share it with your fellow fishing enthusiasts! You never know who it might come in handy for. Also, if you have any questions or comments, feel free to leave them in the comments section below. We love hearing from our readers and greatly appreciate your support!

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