How Often To Change Betta Fish Water?


One of the staples to your betta fish’s health is keeping its tank water clean, which means emptying, and refilling the aquarium. So, it’s essential that you know how often to change betta fish water for a healthier, vibrant, and happier pet. 

Your fish can comfortably live in a filtered aquarium or simple fishbowl, but water changes are important in either instance. Continue reading this article and find out how long keeping betta fish in the same water can be too long, and what you risk when water is left unchanged for a certain time.

Creating a Conducive Environment for Betta Fish

If yours is a betta fish, then you own one of the most vibrant, colorful, and beautiful in the whole world. Betta fish males, in particular, are full of color, always on the move, and an outright show off if there ever was one.

As a fish lover, you and I equally adore the special betta fish. There are many things that you can do, improving the water and quality of life in a betta fish’s tank. 

However, the most significant is how often to change their water, whether it’s in a tank with filtration or a regular bowl. High and hazardous nitrate and ammonia levels tend to collect in unchanged water due to the fish’s waste releases. 

How Often Should You Change Betta Fish Water?

Water changes in a filtration tank should be done at a rate of 10 to 30 percent of the aquarium’s capacity every seven days. Larger tanks, particularly with good filtering systems, will require less frequent changes of water and fewer cleaning. Your large betta fish tank can go two or three weeks without full water recycling if you change 10 to 15 fifteen percent of its contents.

General Practices for Changing Fish Water

The elements that can cause betta disease and stress out your fish aren’t visible to the naked eye. If your tank contains more than one betta fish, the general water quality will need to be primed for optimal fish happiness. 

Your fish need ample space to carry out their antics, making the tank vibrant and colorful all by itself. All it takes is to keep your betta fish’s aquarium is clean and the water quality stellar, and remember not to crowd them too much inside one aquarium.

Ensure you have at least three gallons of water for each fish if you own these splendid fish in multiples. Set up a betta fish tank that holds 10 gallons of water or more, and preferably,  your aquarium should be made from glass or acrylic materials. 

Depending on the presence or absence of a filtration system for your betta fish tank, a general rule of principle is changing water more often the smaller it is. 

Avoid changing betta fish water too often, or changing the complete tank, as you risk interfering with the parameters that are attached to the betta fish tank water. These include temperature, water PH, hardness, and bacterial and other microbial or biological content levels that your betta fish needs to thrive.

Products Needed to Change Your Fish Water

Other than a few live or fake plants in the water tank, there should be lots of space for the display of color that these species are famed for. Changing the betta fish aquarium water should be done in bits to avoid stressing it out.

To efficiently change your betta fish’s water, you will need;

  • One larger bucket that holds the new fish tank water
  • Another bucket wherein you’ll put the water removed from your betta fish’s tank.
  • Water cleaning siphon
  • Water conditioner
  • A fish tank or water thermometer

Make sure that the water you’ll add to the aquarium does not have any chemicals or traces of cleaning products in it. The water you remove from the tank is rich in ammonia and nitrates, perfect for watering plants, or you can throw it away.

Special siphons are available for draining water from your tank. These have the added advantage that you can ‘vacuum’ the bottom to collect waste without risking stress for your betta fish. 

A water conditioner is used to dechlorinate water from your house tap, making it healthy for your betta fish. Use the tank thermometer to ensure that your betta fish’s tank conditions are not significantly affected by the new water by ascertaining the before and after temperatures.

How to Change Betta Fish Water 

It’s not complicated to change your betta fish’s water, especially if you are using the water cleaning siphon I mentioned above. Changing tank water to the required percentage is a quick process once you’ve put together the items you’ll need. 

Here is a simple procedure on how to change betta fish water

  1. Fill one clean bucket with tap water, ensuring you have enough for the amount you intend to replace from your betta fish’s tank. 
  2. Prepare the water in the first bucket by de-chlorinating it with a water conditioner. The chlorine present in tap water will cause your betta fish harm through betta disease and ultimately its demise.

To remove chlorine, follow the water conditioner’s instructions carefully to complete this step. 

  • Remove the old betta fish water from its aquarium, preferably using a cleaning siphon to drain between 20 and 50 percent of your tank’s contents. A gravel siphon also cleans the remaining water, but you can also do it manually if you lack this implement, and then dump the old water into the second bucket.
  • Be keen with this step, as it involves checking that the water temperature remains perfect for your betta fish with the water change. Measure the water temperature with a tank thermometer and match it with that of the new clean water, adjusting by either heating or adding cold water. 
  • Add the clean new water to your betta fish’s tank and bring the level back as it was. 

Changing Your Betta Fish’s Water without Siphoning 

It’s quite easy to change the water for your betta fish without using a cleaning or gravel vacuuming siphon. Although a cleaning siphon helps to remove food bits and other debris that settles on the fish’s tank bottom, it’s not the only alternative. 

Unless you are doing a full water change, avoid pulling your betta fish out of the tank when changing part of the water with or without a siphon. 

Perform the preparation and the first two steps of preparing the new water, and remember to take the temperature before making any change for the remaining water. I strongly advise using a designated bucket that changes betta fish water from new to avoid the risk of cleaning chemical contamination.  

You can tilt your tank and measure the water poured out against the percentage of change you intend to do. A trick is to fill three one-gallon buckets if yours is a 10-gallon tank, translating to 30% of the total water content in your betta fish’s tank.

Risks If You Don’t Change Your Betta Fish Water

Small water changes every week, or another will keep your fish healthy and happy, alongside regular cleaning or maintenance. No matter the effectiveness of your betta fish tank water filter, it’s unavoidable to change your betta fish’s water.

Failing to change your fish’s water causes the buildup of harmful compounds and bacteria, not the best environment for your betta fish to thrive in.  Having to deal with a stressed or diseased fish takes the fun out of keeping your pet, and it’s a lot tougher than a regular cleaning or changing water.

If you don’t change your betta fish’s water at least once or twice a week, you risk; 

Ammonia and Nitrate Buildup

Ammonia is produced by fish through excrement, and this soon turns to nitrite. With time, more ammonia and less effective filtration, nitrite turns to nitrate, which is tough on your aquarium ecosystem to process efficiently.

A buildup of nitrate will stress your betta fish, leaving it vulnerable to poor health, color, or suffering growth and development problems. Routine water changes keep levels of nitrate manageable by your fish’s water tank habitat. 

Decaying Matter Build-Up

When food particles, plants, or your fish’s waste decomposes, toxic nitrogenous by-products are released, including phosphates and other chemicals. A condition such as this is the epitome of poor water quality, which can cause an acidic ecosystem that compromises water PH buffering capacity.

Depleted Essential Elements and Trace Minerals 

Wild waters have a consistent amount of minerals, trace elements, vitamins, and other nutrients. When you’ve neglected to change the water in your fish’s aquarium, these essential elements for their growth become depleted.

Failure to change betta fish water regularly denies your betta fish a fresh supply of vital nutrients and can stunt their growth and vibrancy. 

Frequently Asked Questions 

Why did my betta fish die after I changed the water?

You probably didn’t prepare the water by removing chlorine or ensure that no cleaning chemicals come into contact with your betta fish. Water straight from the tap and using implements that have been washed with cleaning liquids will kill your betta fish.

Aside from that, your fish could also have died from the stress caused by a sudden change of the tank water parameters such as temperature, PH, or acidity levels.

How long can a betta fish go without water change?

In a tank without filtration, don’t leave your betta fish to go for more than a week without a partial water change; where the fish’s aquarium has a filter, two weeks will suffice.

How to change betta fish water bowl? 

The less space in the water container, the more often it requires either a partial or full water change. Changing water from a betta fish bowl is easy, as you only need to pour out about half the contents and refill with treated water from a clean container.


You can opt to do partial water changes as opposed to full cleaning and maintenance, which should be performed but not too often. Changing all the water at the same time will cause stress to your betta fish since the same water parameters can’t be replicated instantly.

In this respect, do not remove your betta fish from the tank unless you are doing a complete or full water change. Stressing your betta fish directly threatens their happiness, health, and survival.

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