How Often to Change Betta Fish Water?

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Keeping the water clean is one of the staples to a betta fish’s health. The better the quality of the water is, the better the quality of a betta’s life will be, which will lead to a healthier and happier betta fish.

There are plenty of things one can do to improve the water quality in a betta fish tank. The biggest and most important factor is obviously water filtration.

A good filter will do a lot for the quality of the water, and will keep it clean in the long run. But, a filter can’t do everything, and regular water changes should be done.

Water changes should be done frequently, and how frequent they should be done depends a lot on the filtration. If you have filtration in your tank, then water changes should be done weekly, and about 10-30% of the water should be changed.

If the tank is unfiltered, you should do weekly changes, and about 30-50% of the water should be changed. That is because the water will inevitably be much worse due to bad filtration.

In this article, we will take a look at everything about water changes in your betta fish tank – how often they should be done, how they should be done, and everything that you need to know about the quality of the water.

Things to Consider When Changing Water for Bettas

There are several things that you should consider when you are changing the water for betta fish.

Firstly, it depends on how much water conditioner you already have in the main tank, and how much water you are willing to change.

Usually, the more water you change, the higher the need for new water conditioner will be. If you add a lot of water at once, then the best thing to do would be to condition it with a conditioner prior to adding the water.

Secondly, the water temperatures of the new water. Betta fish can be sensitive to water changes and water temperature changes, so try to impact the temperatures as little as possible.

When you add a lot of water to the tank at once, you should either heat the water before you add it to the levels of the water tank, or make sure that it isn’t too low for the bettas.

When adding the water to the tank, another thing to consider is the water source. If it is tap water, you should condition it before adding it to the tank.

Distilled water should be avoided, and if you are adding well water, make sure to add conditioners and some chemicals that get rid of the heavy metals in the well water.

Can You do Full Water Change for Your Betta?

Full water changes can be done if there is something really wrong with the water in your current tank. Although that will force you to do other several changes.

Firstly, you will obviously have to move the bettas to another tank while you are changing the water. That requires an additional tank with proper tank conditions.

The second thing to keep in mind is that the water you will be adding should be properly conditioned, and the more water you will add, the more of these chemicals will be required.

Usually, full water changes are not done because they can impact and stress your betta, and it takes some time to get the water into the proper conditions. However, if there is no other option and the full water change is required, then it can be done.

Can You Use Tap Water for Betta Aquarium?

Yes, tap water is often used for betta aquariums. Even though tap water alone, without conditioning, is not a good source of water to use in betta tanks. Obviously, you will need to use a conditioner of sorts to get rid of the unwanted chemicals, especially the chlorine from the tap water that is used in communal waters.

Chlorine can harm fish, especially in higher quantities. Tap water is one of the more convenient options for water changes in betta tanks, and often comprise the largest betta tanks.

Another water source that is commonly used is well water, although that too can contain some chemicals that can harm your fish. These chemicals are heavy metals, which seem to be prevalent in well water. That water will also need to be conditioned prior to put it into the tank.

Distilled water should be avoided, as it doesn’t have the minerals and nutrients necessary for the betta fish tank.

How Long Can a Betta Aquarium Go Without Water Change?

As we have already said, water changes should be made weekly, or at least once per two weeks. That is often the minimum requirement. For good results, weekly water changes are for the best, and it ensures that the water quality stays at a high level.

However, many owners neglect the need to change the water frequently, and only do that when the water only gets dirty. If that happens, it can deteriorate the health of a betta, and you might start to see diseases and unusual behavior.

For these reasons, once a week or once every two weeks is the minimum for water changes. Over time, the water loses the quality and the nutrients for the bettas to live in.

Can You Set up a No-water Change Betta Aquarium?

That can be done, but you will have to make sure of a couple of things.

The first and most important thing is the filtration. If you have strong and adequate filtration, water changes can be less frequent. You should also have plenty of live plants, some creatures that will clean the water such as shrimp.

Still, water parameters should be monitored, despite all these factors. Sometimes, a tank simply can’t go without changing water.


Water changes should be done weekly in a betta fish tank. Good filtration and plenty of vegetation should improve quality. Maintaining good water quality is essential for keeping your little friends healthy and happy.

Author Image Fabian
I’m Fabian, aquarium fish breeder and founder of this website. I’ve been keeping fish, since I was a kid. On this blog, I share a lot of information about the aquarium hobby and various fish species that I like. Please leave a comment if you have any question.
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