How Long Can A Betta Fish Go Without Water Change?

We may receive commissions when you buy through links on our site.

Do you often feel lazy to change the betta tank water for weeks? Know that you’re not alone. Treating and changing betta tank water is the hassle part of petting a betta fish. So, if you consider yourself a procrastinator like most other people of this era, you might want to know how long can a betta fish go without change.

A betta fish can live up to 2 to 3 weeks without a water change if the tank is big with no tankmates. However, if the tank isn’t too big but is well-set up with a power filter, the betta can live up to about a week without a water change.

Anyway, how long can a betta fish go without water change depends on a number of different factors such as the size of the tank, the setup, whether your betta has mates, its eating habits, and so on. Want to know in detail about all these? Let’s get going!

How Long Can a Betta Live Without Changing the Tank Water?

Betta is quite a hardy fish, so, it possesses a good tolerance to water change. However, even if the betta is capable of going at least a week without a water change, you should never delay up to that. Because this will risk your betta’s life and health as the tolerance level of betta is not the same and also it is dependent on a number of factors.

If you have a well-setup and -managed betta tank with proper arrangements for filtration. You can max make 4 to 5 days of delay in changing the water. But this should not be always practiced. Because this might gradually lead to diseases in your betta.

How Often Should You Change a Betta Tank Water?

Changing 10% to 20% of your betta tank water at least once a week is a must when you have a tank with filtration. However, it is ideal to change it twice a week for being on the safer side. But if you don’t have an arrangement for a power filter in your betta tank, then it is better to change at least 30% to 70% of the tank water every week.

Though this is a very general estimation that can’t be considered accurate. Because how often a betta tank water should be changed depends and differs on various factors. To figure out which water-changing schedule would be the best for your betta tank, you need to take several factors into account. Don’t worry we’ll be helping you through it.

Factors that Influence Your Water Changing Schedule

Here are a few of the major factors that play an important role in deciding the right water-changing schedule for your betta tank.

Whether the Tank is a Filtered One

The existence of a filter plays a vital role in figuring out when and how you should change your betta tank water. The filter resists DOC buildup and provides necessary oxygen to the tank water. A tank with a filter doesn’t get contaminated easily.

However, the type of filter you use is also a factor to be looked after. Usually, depending on the existence and type of the filter, you are supposed to decide the percentage of water you need to change. A power-filtered tank generally requires much less quantity of water change than a bio-filtered tank.

Whether Your Betta Has Mates

If you have a single betta in an adequate size tank, it will reduce the calculation for you. However, if your betta shares the tank with other tankmates of either the same type or different, you need to take all of them and their habituations into account as well. Because think about it, if you have just a single betta in the tank, it will release only a small amount of chemical waste.

Also, there will be sufficient oxygen and other resources for its use for a longer time. But there will be more waste with a stretch of resources when the tank is shared. Hence, you’ll need to change the water more times if your betta isn’t living alone along with considering the number of its tankmates.

How Much Have Your Betta Been Eating

The amount of food your betta intakes is an obvious factor here since it is the main source of waste materials for which the water change is required. If you’re overfeeding your betta, there will be more ammonium buildup inside your tank.

When the betta is fed more, it creates more waste from its body, and also the leftover food remains within the tank water which gradually transforms into ammonium. This is extremely harmful to the betta and causes several fatal diseases in it. Hence, if you’re feeding your betta more, make sure you change your tank water more often.

The Size of the Tank

The size of the tank is the initial element to decide your water changing schedule and type. Because depending on the size, you will be able to decide whether your water should partially be changed or completely as well as after how many days.

If your tank is bigger than it is required for the size of your betta. There will be enough water to circulate and diffuse the waste elements. Thus, you can change your tank water after quite a long interval. However, if your tank is comparatively small, the waste elements will get concentrated faster, for which, you will need to change the water more often.

What Water Conditions Do Bettas Prefer?

Bettas are comparatively hardier than many such home décor fishes. This is one of the leading reasons behind their popularity as a pet for home aquariums. They are capable of living in various water conditions and have good adaptability to the changes in the water environment to a certain extent.

Anyways, bettas prefer a comparatively warm temperature. Cooler temperature makes them docile and inactive. Moreover, they are fond of an acidic environment. Though they can also thrive in a slightly alkaline nature they prefer a water pH below the neutral level. Besides, even though bettas are quite hardy, they highly prefer soft water with low GH and KH values.

How to Change Betta Tank Water?

Once you figure out the best schedule for the water change, make sure you know the best-suited method to be used to change your betta tank water as well. You can change your betta tank water in two ways, either partially or completely.

Along with your preference and convenience, you should ensure the type of water change you choose is appropriate for both your betta and the tank. Here goes a short guide to help you through the process.

Required Supplies:

1. Siphon Hose: The siphon hose is used to translocate the tank water from the tank to a bucket. It creates a strong current and can drag your betta as well if it’s small. So, keep an eye on the tank the whole time.

2. Dechlorinator: It is extremely important to treat your water with dechlorinator before placing it into the tank while the water changing if you’re using tap water supplied by your municipality. Because tap water contains chlorine content used for purification which is extremely harmful to the fish.

3. Water Test Kit: To measure and balance out the parameters of your betta tank water as per the requirements of your betta during a water change, you need to have a water test kit. Every time you change your tank water, you need to make sure the water parameters are appropriate for your betta.

4. pH Adjusting Reagents: If you’re using tap water, even after treating it with dechlorinator, you will need to fix its pH according to the preference of your betta fish, for which, you will need pH adjusting reagents.

5. Thermometer: While changing water, temperature shocks might make your betta sick. So, you should keep a thermometer in the tank to match the temperature with the preference of betta fish as much as possible avoiding drastic temperature changes while you’re changing the water.

Method 1: Partial Water Change

  • Collect the new water up to a certain amount that is required to be changed from the tank. That is if you’re about to change 50% of your 10-gallon tank, take 5 gallons of water.
  • Treat and condition the collected water as per the preferred water parameters of a betta fish using water adjustment reagents and if you’re using tap water, then dechlorinator as well.
  • Slightly warm up the water as bettas prefer a water temperature a bit higher than the room temperature. Use a thermometer to match the preferred temperature.
  • Draw out some water from your betta tank depending on its size using a siphon hose. Usually, the ideal percentage of changing water is 25% for a standard-size betta tank.
  • Now, refill the water with the freshly treated water gently using a bowl or scoop. Make sure you don’t pour the water harshly and disturb your betta making it restless.

Method 2: Complete Water Change

  • Collect the new water up to the amount of your tank water. That is, if your betta tank is of 10 gallons, take 10 gallons of water.
  • Treat and condition the collected water as per the preferred water parameters of a betta fish using water adjustment reagents and if you’re using tap water, then dechlorinator as well.
  • Slightly warm up the water as bettas prefer a water temperature a bit higher than the room temperature. Use a thermometer to match the preferred temperature.
  • Transfer your fish from the tank to a temporary container using a fish net before changing the water. Try to be very careful as you can injure your betta fins while removing it.
  • Now thoroughly remove the tank water and clean your tank using tap water and a soft sponge. It’s better not to use soap or detergents as leftover chemicals from them might harm your betta.
  • Pour a portion of the water you freshly prepared for the tank inside the tank. Ensure you pour just enough for the fish to move and swim comfortably.
  • Move your betta fish back to its tank gently using the fishnet.
  • Then, pour the remaining freshly prepared water gently into the fish tank using a bowl or scoop without disturbing your betta.

Which is the Best Way to Change Betta Tank Water?

The most preferred way of changing the betta tank water is through the partial water change method. Because the partial water change reduces the shock your betta goes through from a water change.

The old tank water contains different enzymes released from the betta that helps the betta swim smoothly and makes the water more comfortable for them. Since in partial water change, the water is changed and diffused gradually bit by bit, the betta doesn’t go through much shock and adapts to the freshly inserted water gradually.

Moreover, partial water changing also doesn’t have any risks of injuring your betta fish as you don’t need to transfer it to a temporary tank. Complete water change on the other hand might cause shock and stress in your betta making it restless and uncomfortable.

Therefore, partial water change is more encouraged than complete water change for a regular or weekly water change. However, if your betta tank is too small or is too dirty and requires cleaning, then you shall go for a complete water change on such occasions.

How to Change Betta Fish Water Without Siphon?

If you don’t have a siphon to remove a certain portion of water from your betta tank while partial water changing, you can also use a bowl or scoop for this purpose. But you need to make sure the bowl is clean without having any soap or detergent residues in it. Moreover, make sure you remove the water from the tank using the bowl really gently without disturbing your betta.

Siphon is highly preferred for this process because firstly, it is much more hassle-free. Secondly, a siphon is gentle and accurate. When you’re using the bowl, you might find it difficult to accurately estimate the required portion to draw.

Why is Water Change Important for Betta Fish?

Changing the betta tank water is also called spring cleaning. It is required because just like when we are in a confined room, we cannot survive without an oxygen supply from outside after a certain time as the oxygen gets reduced and the air gets polluted by other harmful compounds, it also happens with the fish.

The fish water gets polluted by the wastes and excretion from the fish, dead plants, uneaten food, and other natural dirt buildups. This reduces the oxygen level in the tank water and increases the ammonium level. This is extremely harmful to your fish making it vulnerable to several fatal diseases.

Thus, partial water change works as an oxygen supply and toxins removal for the fish to remain healthy inside the tank.

Can a Betta Survive in Dirty Water?

As a betta fish can be really hardy and adaptable to severe conditions, it might survive in dirty or unchanged water for up to 3 to 4 weeks. But after that, it will get extremely uncomfortable and suffocate as the oxygen level will reduce and the ammonium level will increase. The betta will get restless and might even try to jump out of the tank sometimes if there isn’t any lid on it.

Moreover, it will gradually, deteriorate the health of your betta and damage its gills. This often leads to severe damage to fish along with higher chances of death. Thus, no matter how hardy the betta is, water change is extremely important and an inevitable duty for taking care of a betta fish.

How Much Water Should Be Changed (Based on Tank Size)?

Here’s a standard percentage of the amount of water required to be changed based on the size of the betta tank for your convenience.

  • 5 Gallons or Smaller: 40% to 50%
  • 10 Gallons or Higher: 20% to 30%
  • Larger than 20 Gallons: 15%

Final Words

Always remember, how long can a betta fish go without water changes varies from one fish to another. Not all betta fishes have the same level of adaptability. Hence, it is better not to risk it by procrastinating. You are responsible for your betta’s life and well-being. So, make sure you serve it well while you’re hosting it.

Leave a Comment