Do Aquarium Filters Oxygenate The Water? (How Exactly?)

Image of an aquarium filter being cleaned

Most aquarists use aquarium filters to purify the water. But do aquarium filters oxygenate the water?

Yes, aquarium filters oxygenate the water. They create water movement at the tank’s surface for the gas exchange to occur, thus increasing the oxygen levels of the water. Aquarium filters also help circulate the water from the bottom to the top and throughout the tank so that it’s well oxygenated.

Let’s now delve deeper to understand how filters oxygenate the water.

How Do Aquarium Filters Oxygenate The Water?

Gas exchange occurs at the water’s surface by taking in oxygen from the air and releasing carbon dioxide from the water.

For this gas exchange to happen efficiently, the surface tension of the water must be broken.

Aquarium filters help create the agitation required for breaking this surface tension, thus oxygenating the tank water.

Moreover, stagnant water has lower oxygen levels. The lack of water movement usually results in low oxygen levels at the bottom of the tank. So you can sometimes see the fish gasping at the top of the tank for oxygen.

This is also where aquarium filters help as they circulate the water in the tank.

Water circulation moves the water from the bottom to the top to increase the oxygen concentration. This ensures that the entire tank water is adequately oxygenated.

In the wild, fish live in large water bodies with large surface areas and a strong current that keeps the water moving.

So you won’t often find reduced oxygen levels in a fish’s natural environment.

Alright! Now that you know filters can oxygenate the tank water, you may wonder if it’s essential to have an aquarium filter to maintain the oxygen levels.

Recommended Further Reading:

Do You Need An Aquarium Filter For Oxygenating The Water?

Aquarium filters are not required to oxygenate the tank water if you have an efficient aquarium air pump.

They are primarily used to maintain the water quality by removing the toxic buildup of ammonia and nitrates, debris, and other impurities from the water.

Aquarium filters help oxygenate the tank water, but they’re not the only way to increase the oxygen levels of the tank water. There are several ways to oxygenate the tank water without an aquarium filter.

The easiest and efficient way to manually increase the oxygen in the tank water is by slowly pouring the water into the tank from some height.

When you pour fresh water into the tank, it picks up the air en route and drives oxygen into the tank water.

Another way is to have a 50% water change to increase the oxygen levels of the tank water. The newly introduced water will usually have more oxygen compared to the existing water in the tank.

Putting some ice cubes in a zip-closed bag and holding the bag in the aquarium also help increase the oxygen levels of the tank water.

This method is mainly used when the temperature of the tank water increases. Warm water contains less oxygen compared to cool water.

Adding live plants is yet another natural way to increase the oxygen levels of the tank. Mostly all aquatic plants produce oxygen.

However, submersible aquatic plants introduce more oxygen than floating plants as the former release oxygen directly into the water.

Some of the plants that oxygenate the tank water are:

  • Hornwort,
  • Ludwigia Repens,
  • Anacharis,
  • Anubias,
  • Java Fern,
  • Dwarf Sagittaria,
  • Green Cabomba, and
  • Jungle Vallisneria.

Related Further Reading:

Do Canister Filters Oxygenate The Water?

Canister filters are ideal for large fish tanks. While canister filters don’t directly increase the oxygen in the tank water, they definitely help increase the oxygen levels.

Canister filters create the surface agitation that’s required for the gas exchange to take place at the water’s surface. This helps boost the dissolved oxygen levels of the tank water.

You can position the canister filter’s return pipe directed towards the surface. This will create surface agitation and water movement in the tank, thereby resulting in more dissolved oxygen in the tank water.

Additionally, canister filters have a high flow rate and multiple filtration systems. Therefore, you can apply biological, mechanical, or chemical filtration with the help of canister filters.

This helps maintain the water quality and oxygenate the tank water at the same time.

Can You Switch Off The Aquarium Filter At Night?

It’s not advisable to switch off the aquarium filter at night or during the daytime. Aquarium filters need to work 24/7 to keep the water clean and the fish healthy.

An aquarium filter’s primary purpose is to clean the water by removing impurities from the tank that causes stress to fish.

If you switch off the filter at night, there won’t be any way to clean the fish waste that builds up throughout the night.

Apart from maintaining the water quality, an aquarium filter also assists in aerating the water. Oxygen is crucial for the fish to thrive.

Moreover, an aquarium filter also protects the healthy bacteria that break down the ammonia into less harmful nitrate. The filter is one of the main places where the healthy microbe colonies thrive in the tank water.

Another advantage of keeping the filter on throughout the night is that it also helps in circulating the water.

Water circulation results in increased oxygen levels in the tank water. If you switch off the aquarium filter at night, you are depriving the fish and microbes of oxygen.

Switching off the filter for a day or two during the night may not harm the fish or microbes to a great extent. However, if you switch off the filter every day at night, it can harm them.

Interesting Further Reading:

Should You Turn Off The Aquarium Filter When Feeding The Fish?

The type of aquarium filter and its position in the tank determines whether it needs to be switched off during the feeding time.

Most internal filters return water horizontally in the tank, resulting in water movement across the tank. This means that if you are feeding your fish any sinking food, it will remain suspended in the water for a while before it finally sinks.

External filters also function on similar lines. However, they are more adjustable. You can position their spray bar or the return pipe in such a way that it sends the water straight down to the tank floor. This will sink the food rapidly in the tank.

So, if you have bottom-feeding fish like corydoras, it won’t matter much if you keep the aquarium filter on. On the contrary, if you have top or middle-feeding fish such as guppies, you can switch off the filter while feeding them.

If you switch off the filter while feeding the fish, make sure to switch it on immediately after the feeding is over.

Another alternative is to feed the fish in small quantities so that they can gobble up most of the food before it reaches the bottom of the tank.

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