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Can You Put Too Much Air Into a Fish Tank? Complete Answer

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Oxygen is needed for the survival of all living beings, including fish. Despite what people think, just because fish live underwater doesn’t mean they can go without oxygen.

Yes, you can put too much air into a fish tank. Fish, like all other living creatures, need oxygen in order to survive. However, you can put too much air in a fish tank. Too much air in a fish tank can cause widespread disease throughout the tank. An oxygen level between 200 to 500 mg is needed. 

Read on to learn more about keeping the oxygen level in the tank at a normal range and how to tell if there is a problem in the first place!

Do Fish Need Oxygen?

Like people, if fish are deprived of oxygen for too long they will die. Fish need oxygen in their water for their metabolic process, digestion, and growth.

Fun fact, it takes fish a lot more energy to “breath water” than it does for us to breathe air. This is because there is 95% less oxygen in water than there is in air, also water is 800 times denser than air!

Airstone in aquarium

Breathing water is made easier through the structure of the gill, this allows them to take 80% of the oxygen from the water they pass through.

Different environments have different levels of oxygen in the waters, fish will tend to hover around in areas that have more oxygen.

How Much Oxygen Do Fish Need

The amount of oxygen in water is dissolved oxygen, this is measured in percentages. Ensuring there is oxygen in your tank is important for your fish to thrive, but too much can cause problems or disease. 

Because there are so many different species of fish, there is no definite level of oxygen for a baseline. However, an oxygen level of 200 to 500 mg of oxygen per hour per kg of fish is the average. 

For example, a goldfish can handle low oxygen conditions for a longer period of time. They are able to do this because their bodies are built to get oxygen to their tissues more efficiently. 

Gouramis are another fish that can handle even lower oxygen levels than goldfish. They actually evolved in low oxygen conditions in Southeast Asia, and they have a labyrinth organ in order to get more oxygen.

However, there is a general rule that larger fish need more oxygen per hour than smaller fish. Faster smaller fish require more oxygen than slower smaller fish as well.

Most of the time the fry will also require less oxygen than their adult counterparts. 

There are also many different factors besides breed that vary the amount of oxygen needed in the water. Temperature affects how much oxygen is needed. The higher the temperature, the more oxygen is needed.

Feeding times can also affect the oxygen needed, as more oxygen is used during this time. 

How to Tell If There is Too Much Oxygen

Too much dissolved oxygen in the water is also known as hyperoxygenation, which can be caused by people or naturally as well.

Even though the presence of hyperoxygenation is harder to tell inside a tank, there are signs that you look out for.

The best way to tell if there is dissolved oxygen in your tank is to simply observe your fish. By observing your fish if you notice a difference in their behavior or their appearance/ health you can determine if there is too much oxygen.

Your fish may act differently if there’s too much-dissolved oxygen in the water. Such changes are:

  • Abnormal swimming patterns
  • Open mouth breathing
  • Lethargy
  • Excessive appetite
  • Swimming to the surface to breath
  • Eating more slowly

These are health signs that you can look out for as well in your fish:

  • Unexplained deaths
  • Bloating- Too many gas bubbles get stuck beneath the scales resulting in swelling.
  • Cloudy eyes- When there is a lack of carbon dioxide in the water, the fish cannot see as well.

How Does Too Much Oxygen Affect Fish?

As previously mentioned, too much oxygen not only affects the behavior you see in your fish but also affects their health as well and can result in death. Hyperoxygenation can affect the balance in the fish tank including fish, plants, and coral. 

This is because when there is too much dissolved oxygen present, that means the carbon dioxide levels have also dropped. H

yperoxygenated waters stress fish, invertebrates, and other organisms and can result in death if not taken care of. 

The more oxygen in the water the less active the fish in your tank will be, this will also increase their metabolism rate.

When this happens it can lead to an ammonia buildup, which is poisonous to fish, disrupting their breathing even more.

Too much oxygen can also put your fish under stress. When a fish is stressed they are more likely to catch a multitude of diseases. This can result in the death of multiple fish inside the tank.

As mentioned previously, too much oxygen means there is less carbon dioxide. Plants in the tank need carbon dioxide to live, through photosynthesis.

When there is too much oxygen then the plants will slowly die off causing decay and affecting water conditions for your fish.

Bubbles on plant

How to Avoid Too Much Oxygen

There are many steps that you can take to prevent too much oxygen in your tank.

With a suitable initial tank setup, as well as regular maintenance on your tank can help prevent too much oxygen. The following are some examples:

  • Using a filter or powerhead to circulate the water, keeping water from sitting in one spot too long. This can also help with less bloating, as there will be fewer gas bubbles stuck under scales.
  • Maintenance is key! Keeping up with your regular water changes as well as monitoring the water parameters in your tank help prevent hyperoxidation. If you notice that even with regular water changes you have too much oxygen, try doing your water changes more frequently.
  • Installing a bubbler or an airstone near the surface of the water, one that can emit bubbles into the water column. This pulls excess oxygen from beneath the scales on the bodies of your fish.
  • Changing the lights in your tank to fluorescent bulbs can help reduce oxygen levels as well. Some lighting such as LEDs, includes UV waves that can cause significant damage, killing off good bacteria in your tank. Other lighting can cause heat as well, which also affects oxygen levels.
  • Monitor your fish tank, and look out for signs of too much oxygen. The signs of too much oxygen are the same as when ammonia and nitrate levels are too high.

Of course, on top of all these steps, it is also very important to monitor the fish in your tank all the time. This is when you will pick up on behavioral changes, health changes, as well as changes in the balance of your tank, or even unexplained deaths.

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