How Often Do You Clean a Betta Fish Tank For Optimum Health

How Often Do You Clean A Betta Fish Tank

You’ve probably heard that you should clean your betta fish tank every week, and some betta owners will advise you to clean your tank once per day. With so much advice out there, who should you listen to, and what are the facts? How often do you need to clean a betta fish tank?

A betta fish tank should be cleaned as often as necessary to keep the tank clean and remove any accumulated debris. Each tank is different and will depend on several factors such as:

  • The Size of the tank – Usually, the bigger the tank, the less often in needs cleaning.
  • Does your tank have a filter? – Filters will help to keep a tank cleaner for longer.
  • Is your betta tank well planted – Plants aid in the bioactivity of your tank.
  • How bioactive is your aquarium? – The more bioactive, the more it sustains itself.
  • How many fish in your tank? – More fish equates to more waste build up.

As a general rule, a small betta tank 1-10 gallons without a filter and plants should undergo a 20 percent water change every 2 days. If you have a filter and live plants, you can change the water every 1 week.

Up to 50 gallons without filter or plants, again you are looking at a water change every 2-3 days, and with filter and live plants, you may not need to clean your tank for 2 weeks.

Every aquarium is different, and there is no definite answer, so throughout this post, I will explain everything you need to know so that you can figure out how often YOUR betta tank needs to be cleaned to keep your betta healthy.

If you are interested, I have a more in-depth guide to cleaning a betta tank which you can read here: How Often To Change Betta Water – What you need to know.

Also, make sure to check out our Betta Fish Care Guide And Species Overview.

(Guide)To Betta Tank Cleaning Frequency

I say guide because no definite rule fits all, but the table below will help you with some very general guidelines based on how often other aquarists clean their tanks.

Aquarium SizeCleaning Frequency
Without Filter
Cleaning Frequency
With Filter
1-5 Gallon10-20% Every 2-3 Days20% Once A Week
5-10 Gallon10-20% Twice a week20% Once A Week
10-20 GallonRequires A Filter25% Every 1-2 Weeks
20-50 GallonRequires A Filter25% Every 2-3 Weeks
50% Every 8-12 Weeks
50+ Gallon Requires A Filter 25% Every 4 Weeks
50% Every 8-12 Weeks
Typical Cleaning Frequency Guide For Betta Tanks

How Often Do You Clean A Betta Fish Tank – Understanding Your Tank

Understanding your own betta tank is an important step to knowing when to clean it. Every tank has its own level of bioactivity, and this will determine how often you should clean it- the higher level of bioactivity in your tank, the less you need to clean.

What is a bioactive fish tank

A bioactive fish tank will produce its own self-sustaining atmosphere/environment, such as you would find in nature. A human would not need to change the water or clean the gravel; the only thing we might do is feed the fish.

Bioactivity within a betta tank can be increased by having live plants, adding gravel to your aquarium, and ensuring there are plenty of hiding places for your betta fish. A bioactive tank will also have nitrifying bacteria that break down ammonia into nitrogen. If you watch your ammonia levels, you will know how often to clean out the tank.

Gravel is also a good place for the beneficial bacteria to grow, where much of the waste becomes trapped.

Beneficial bacteria will do wonders for the bioactivity of your betta tank
Beneficial bacteria will do wonders for the bioactivity of your betta tank

Fish produce ammonia as a waste product and can be lethal at high concentrations in an aquarium. Ammonia needs to be broken down into nitrite and then nitrate before it becomes harmless nitrogen gas released into the atmosphere through filters or water changes.

When you have a bioactive tank with all its natural, beneficial bacteria, your ammonia levels should never rise above 0.25 ppm (parts per million). If this level is reached, you need to clean out the tank so that the nitrifying bacteria can disperse into other parts of your aquarium again, i.e., gravel, filter, etc.

Nitrate is the final product of this nitrogen cycle and can often rise above safe levels for fish if your tank becomes dirty or overpopulated or too much food is being given to your betta. If nitrate levels get too high, you will need more frequent water changes to drop down again into a safe range.

Beneficial Bacteria

A highly bioactive fish tank will contain high levels of beneficial bacteria, which will:

  • Fight off bad bacteria.
  • Eating up leftover fish food, and other debris.
  • Helping to keep your tank clean by breaking down waste material and turning it into nutrients for plants or algae.
  • Helping to reduce levels of ammonia, nitrates and nitrites, so increasing levels of dissolved oxygen within the water.


Live plants are also common to see in very bioactive fish tanks and help by:

  • Enhancing oxygen levels.
  • Enhancing water quality by helping to absorb ammonia and nitrates.
  • Reducing the toxic load of an aquarium with their root systems which are effective at absorbing ammonium from fish waste.
  • Live plants also provide a hiding place for your betta while increasing the surface area available for good bacteria growth within your tank, making it even more bioactive.


Lighting is essential if you want a bioactive tank. Fish have their own circadian rhythm and require night and day to keep their bodies ticking over smoothly.

Plants also require light and photosynthesize light during the day, producing oxygen whilst producing carbon dioxide through the night. It all adds up to create your own bioactive environment.

It is challenging to get a completely self-sustaining betta tank because you would have to emulate the natural conditions perfectly. Still, the more bioactive your tank, the less often you will need to clean it.

A new tank may take many months before it reaches a good level of bioactivity.

Do Bettas Need A Filter

Using a filter in your betta tank will be beneficial for many reasons, even though betta fish don’t actually need a filter. If we have a quick look at what a filter will do for your betta tank, you will have a better understanding of its benefits:

  • Filters will keep your betta fish safe from water born diseases. They will also help to reduce stress by removing toxins such as ammonia and nitrite, which are harmful to your bettas.
  • Filters remove solid waste material using mechanical filtration i.e – they strain it out of the tank; this is an extremely important part of keeping a clean tank.
  • Filters also provide oxygen to the betta fish: this is because they are constantly moving water around which aids gas exchange at the surface level of your aquarium where there is more dissolved oxygen. This in turn will keep your betta very happy.

So having a filter in place will definitely reduce the frequency of your tank cleanings.

Do Bettas Need A Heater

Betta fish are a tropical species, so a warm water temperature will be necessary. Ensuring that the water temperature is at its optimal (78-82°F/26-28°C) will help your betta’s natural biological functions and general health remain at its best.

Having the right temperature will also help all the bacteria in the water to thrive, especially the good bacteria. If the temperature is set too high, it will kill many forms of bacteria, parasites, and diseases which is helpful if your betta can tolerate it.

check your aquarium temperature
Check your aquarium heater temperature.

You will need a tank thermometer to monitor the temperature and ensure it remains consistent. Betta fish are good at tolerating temperatures outside their usual range, provided it doesn’t fluctuate too much.

Warm temperatures are also good for plant life, but algae will be encouraged to grow if temperatures are too warm for too long.

How Often To Feed Bettas

Overfeeding your betta is often to blame for excessive cleaning of your betta’s tank. Too much food will become waste and get in the aquarium gravel where it will rot, causing a rise in ammonia and nitrite to toxic levels. At this stage, you will need more frequent water changes so that they drop down again into a safe range.

A highly bioactive fish tank will contain high levels of beneficial bacteria, which will help to eat up leftover fish food and other debris, but the bacteria will not manage this alone. Overfeeding does not happen in a betta’s natural habitat, and it shouldn’t happen in captivity.

So How Often Do I Clean My Betta Tank

With everything I have said, it kind of throws a spanner in the works and makes it difficult to give an ideal timeframe for cleaning a betta tank based on its size.

To be helpful, I have included a table at the top of this post with general guidelines only and for average tanks only.

All of the guidelines and estimations given by others are simply just that. As I have mentioned, each betta fish tank is different, and by testing the water quality in your tank regularly, you will know how often it will need to be cleaned.

There are always exceptions to the rule, and water changes may be necessary more frequently, especially if oxygen levels drop significantly or disease is present in the tank, but if your tank is very bioactive, you may not need to clean it very often.

If you own a smaller aquarium, planting it and adding a filter may not be possible, so you will not get the level of bioactivity you require. A smaller body of water will also be susceptible to sudden changes in temperature and chemistry and will need frequent cleans.

There are complete water testing kits available for every scenario. You can test water pH levels, test for chlorine and other chemicals, and test the oxygen content in the water.

aquarium water test kits
Use a test kit to test your fish tank water parameters regularly

If your tank is stable and you are not overfeeding, you will know that when these levels begin to fall outside the optimum ranges, or if your tank looks dirty, it will need to be cleaned. If you are fortunate, these intervals will remain consistent.

Betta Tank Maintenance And Cleaning

The reason for this article is not to explain the process of cleaning your betta aquarium, but as cleaning is part of what I am covering, I will quickly talk through the cleaning process.

  1. Clean your betta tank thoroughly including the tank glass with a clean sponge or cloth, inside and out. Don’t use any household cleaning chemicals as it will poison your fish.
  2. Remove ornaments that can be rinsed with tap water and clean all the decorations.
  3. Use a gravel vacuum to siphon through the gravel substrate, removing plant waste, uneaten food waste and fish waste.
  4. Using the tank cleaning siphon, remove up to half the tank water into a clean bucket.
  5. Clean the filter media by rinsing under tap water and if using a sponge filter, ensure you submerge in the old dirty water before returning to the tank. It is full of beneficial bacteria and this will ensure the bacteria reinhabits the filter sponges before being returned.
  6. Discard the old water and fill the bucket with clean tap water to bottled drinking water.
  7. Add warm water to match it to the water in the aquarium and a suitable water conditioner. Unconditioned tap water will contain chlorine and other chemicals harmful to your betta aquarium.
  8. Add the replacement water slowly to the tank. Add half the water, and then the remaining water, so as not to unsettle your betta too much.
  9. Clean the tank glass of any splashes with a paper towel to avoid streaking.

There you go! Your betta fish water should be much cleaner, and by doing smaller water changes, you won’t lose all that lovely beneficial bacteria you have worked so hard to get.

How To Clean A Betta Fish Tank
Use a gravel vacuum to clean the gravel thoroughly.

You can remove your betta into a temporary container if you are doing a larger water change or just prefer to. You will need to gently scoop him out with a net.


Hopefully, you have found this post helpful and informative. If you have taken away anything, I hope you understand that what you read or are told are just basic guidelines that apply to most tank setups.

Each tank has its own biological cycle, which depends on many factors working together, so you should gauge how regularly your tank needs to be cleaned with a little testing and consistency with feeding.

If you have a very bioactive tank, you are very lucky and are definitely doing things right. As your reward, tank cleaning may only be required once every 3-4 weeks; otherwise, you may find you will be cleaning it twice a week.

Frequently Asked Questions

Jon O'Connell

I have kept both marine and freshwater fish and set up almost 100 aquariums. Happy to share my knowledge and experience to help others enjoy keeping healthy and happy fish.

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