How to Change Your Betta Fish Water

Co-authored by Craig Morton

Last Updated: October 29, 2022 References Approved

One of the most important things to learn when taking care of a betta fish is how to properly change the water in its tank or bowl. Dirty containers are unhealthy and can make your betta sick, but changing its water improperly can also cause the fish harm. There are two methods for changing a betta’s water: a partial water change, and a total water change. The partial water change is usually preferable, as totally new water can shock the fish.

Method 1

Method 1 of 2:

Doing a Partial Water Change

1
Prepare the new water.^{[1]
X
Research source} Fill a large, clean container with fresh water. Leave your betta’s current container alone for now. Use a water conditioner (available at pet supply stores) to remove chlorine and other harmful substances from the fresh water.
- Follow all directions provided with the water conditioner, and use the exact amount required for your tank or bowl size.
2
Allow the water to warm up. Putting your betta immediately into water that is a different temperature can harm it. ^{[2]
X
Expert Source

Craig Morton
Aquarium Specialist, Aquarium Doctor Inc.
Expert Interview. 21 July 2020.} Let the container of fresh, treated water sit at room temperature for an hour so that it will be safe and comfortable for your fish.
- Alternatively, you can mix hot and cold water from your tap until it is the same temperature as the water in your betta’s current container.^{[3]
  X
  Research source} If you follow this method, use an aquarium thermometer to make sure that the water in both tanks is the same temperature, and add water conditioner to the new water as instructed.
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3
Remove some water from your betta’s current container. To do a partial water change, you will take some of the water from your betta’s container and replace it with some of the fresh, treated water. Using a clean scoop or something similar, remove 25 percent of the water in your betta’s current container. ^{[4]
X
Expert Source

Craig Morton
Aquarium Specialist, Aquarium Doctor Inc.
Expert Interview. 21 July 2020.}^{[5]
X
Research source}^{[6]
X
Research source}^{[7]
X
Research source} Leave your betta in the container as you remove the water.
- To be precise, you can measure the water as you take it out. For instance, if you have a twenty-gallon tank, remove up to ten gallons measured using jugs or other measuring containers.
- You can also use a siphon hose to transfer water from your betta’s container to a bucket or sink. Once the water starts flowing, move the hose so it "vacuums" the gravel at the bottom of the tank, picking up fish waste, old food, and other debris.
4
Refill your betta’s container. Slowly pour fresh, treated water from the container you prepared into your betta’s current container until it reaches the previous water level.^{[8]
X
Research source}^{[9]
X
Research source}If the container is too heavy to lift and pour, use a clean scoop (or similar container) or siphon hose to add the water. It is fine to leave your betta in its container as you add the fresh water, but add the water slowly so that you do not disturb the fish.
5
Repeat water changes frequently. Most experts recommend changing your betta’s water at least once a week. ^{[10]
X
Expert Source

Craig Morton
Aquarium Specialist, Aquarium Doctor Inc.
Expert Interview. 21 July 2020.}^{[11]
X
Research source}^{[12]
X
Research source}^{[13]
X
Research source} If for some reason your betta’s container becomes especially dirty, however, you may need to change it more frequently.

Method 2

Method 2 of 2:

Doing a Full Water Change

1
Prepare the new water.^{[14]
X
Research source} Fill a large, clean container with fresh water. Leave your betta’s current container alone for now. Use a water conditioner (available at pet supply stores) to remove chlorine and other harmful substances from the fresh water.
- Follow all directions provided with the water conditioner, and use the exact amount required for your tank or bowl size.
2
Let the water warm up. Putting your betta immediately into water that is a different temperature can harm it.^{[15]
X
Research source} Let the container of fresh, treated water sit at room temperature for an hour so that it will be safe and comfortable for your fish.
- Alternatively, you can mix hot and cold water from your tap until it is the same temperature as the water in your betta’s current container.^{[16]
  X
  Research source} If you follow this method, use an aquarium thermometer to make sure that the water in both tanks is the same temperature, and add water conditioner to the new water as instructed.
3
Transfer your betta from its container. Using a fish net, remove your betta from its current container to the container filled with fresh water.^{[17]
X
Research source} Be very gentle when moving your fish, as its fins are very susceptible to injury.
4
Clean the betta’s container.^{[18]
X
Research source} Pour out the old water from your betta’s container. Gently clean the container itself, using only water and a clean, soft cloth or sponge; soaps and other products can harm your fish. Make sure to sift the tank’s gravel to remove waste, food debris, etc.
5
Begin filling the betta’s container. Take some of the fresh water from the container your betta is currently in, and pour it into its container.^{[19]
X
Research source} Pour enough so that your betta will be able to move comfortably in its container.
6
Transfer your betta back to its container. Using a fish net, move your betta from the holding tank back to its container, now partially filled with fresh water.^{[20]
X
Research source} As before, be very gentle when moving your fish.
7
Pour the rest of the water into your betta’s container. Take the rest of the fresh water from the holding tank and very slowly pour it into your betta’s container. If the container is too heavy to lift and pour, use a clean scoop (or similar container) or siphon hose to add the water. It is important to pour very slowly so that you do not disturb your fish.^{[21]
X
Research source}
8
Repeat full water changes as needed. Most of the time, partial water changes are all that are needed for a betta's container.^{[22]
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Research source}^{[23]
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Research source}^{[24]
X
Research source} Complete a full water change, however, if the container becomes dirty all over.

Expert Q&A
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Question

How often should I change my betta's water?

Craig Morton
Aquarium Specialist, Aquarium Doctor Inc.
Craig Morton is the CEO of Aquarium Doctor Inc. based in Huntington Beach California and servicing Orange County, Los Angeles County, and the Inland Empire. With over 30 years of aquarium experience, Craig specializes in creating custom aquarium designs along with aquarium installation, service, and maintenance.

Craig Morton

Aquarium Specialist, Aquarium Doctor Inc.

Expert Answer

Support wikiHow by unlocking this expert answer.

I would recommend doing a partial water change once every week. For unfiltered bowls, change 30-50% of the water, and for filtered tanks, change 20-25% of the water.
Question

How do I get the bubbles out of the water?

Shadow_wolf_52

Community Answer

You don't need to; these are a sign of happiness from your betta and are healthy.
Question

Can I use tap water that is filtered?

Community Answer

Not unless you also use a water conditioner.