betta fish in a clean tank

Basic Guide In Cleaning Your Betta Fish Tank

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Every fish tank requires maintenance; some require more than others, but whether it’s a water change every week or topping a tank off every month, the success of most tanks is the reflection of how much time you give them. Regular water changes, substrate vacuumings, and filter media replacements are just some of the most common steps you will need to take to keep your tank stable. Luckily, these processes aren’t hard and usually lead to a thriving ecosystem.

Keep reading to find out why you need to clean your betta fish tank and how to make sure you’re doing it right!

The basics

It might seem like betta fish are one of the easiest pets you could own, but like any other animal, they still require care and upkeep. Cleaning up after betta fish isn’t as simple as cleaning up after a dog or cat though, and needs some practice to get right. But first, you need to understand why a clean tank is necessary in the first place!

Why do you need to clean your betta fish tank?

For the most part, fish tanks are self-sufficient ecosystems that run themselves with the help of nitrifying bacteria, converting ammonia to nitrates. In order to understand why you need to clean your tank, you need to place your small enclosed ecosystem in the context of your betta’s natural environment in the wild.

In wild aquatic habitats, there is a constant importation and exportation of nutrients/minerals, wastes, and gasses, due to flowing water, sediments, evaporation, weather, and other flora and fauna. In our small little fish tanks, there is no input other than what we introduce into the system, and export is typically handled by filter media and/or plants and corals. Hobbyists have solved this problem by performing weekly or biweekly water changes.

Water changes allow for new nutrients/minerals to enter the system while getting rid of those that have built up over time. For example, nitrates. Nitrates are constantly being created by way of the nitrogen cycle that converts ammonia to nitrite to nitrate. As nitrifying bacteria does not process nitrate, it is left to build up in the tank and can become toxic at extreme levels. While nitrates are uptaken by plants and corals, hobbyists will usually still need to perform water changes to keep the nitrates in their tanks from building up.

Similarly, water changes help replenish oxygen levels within the tank. Usually surface water agitation, by way of a filter, air stone, or powerhead, is used to increase gas exchange. Water changes help create movement through the tank and introduce new gases through the new water. As pH is related to how much carbon dioxide in the tank water, water changes can also help stabilize pH and/or increase pH if needed.

How often do you need to clean your betta fish tank?

While all these elements seem like a delicate balance, water parameters in mature tanks stay relatively stable when water changes are regular and aquarium maintenance is maintained. That being said, how often you will need to clean your betta fish tank is up to the tank itself.

How often you need to do a water change depends on the size of the aquarium, filtration, water circulation, bioload, feeding habits, and much more. In general, it is recommended to do 10-25% water changes every week or every other week. Some hobbyists are able to get by only doing monthly water changes, while others don’t do any at all. This is entirely based on the amount of waste produced and uptaken in the aquarium.

If your betta tank starts growing algae, it is usually recommended to increase the frequency of water changes to help remove excess nutrients; at the same time, it is also important to search for the cause of the excess nutrients. Algae is usually the result of high nitrates or phosphates and too much lighting and/or the wrong light spectrum.

man cleaning aquarium using magnetic fish tank cleaner

How to clean your betta fish tank

So it’s time for your first routine tank cleaning! It can be a little scary, but after a few tries, you’ll be able to perform a water change in a short amount of time with little to no hiccups along the way! Here are the easy steps involved with cleaning your betta fish tank (order may change with personal preference):

  1. Prepare new water. It is usually recommended to have the new tank water prepared and ready to go when you go to clean your betta tank. This will mean heating the water to match the temperature of the tank and adding de-chlorinator. At the same time, you may also unplug any equipment in the aquarium so that they don’t burn out and so there is no danger to yourself.
  2. Start a siphon. Once your water is ready and all equipment is safely turned off, it is time to start taking water out from the tank. This can be done by using an aquarium vacuum or airline tubing. Alternatively, you may also use a cup to slowly remove portions of water.
  3. Scrub for algae. While you are siphoning water, you may also take the time to scrub the sides of your aquarium, removing any algae that you can see. This is so that if larger pieces of algae come off, they will be sucked up and removed from the tank as well.
  4. Vacuum the substrate. It is also a good idea to use this time to vacuum and clean the substrate. Cleaning the substrate will keep dead zones and detritus from piling up, which can often lead to algae problems or other excess nutrients. Overturning the substrate will also help with gas exchange.
  5. Waft hard-to-reach places. If you have decorations that are close to the wall of your tank or areas where water flow isn’t good, make sure to gently waft water into those areas to flush out debris. Many hobbyists use turkey basters for the same effect. It may also be a good idea to vacuum the surface of the substrate or use a fish net to catch loose particles afterward.
  6. Wash/replace filter media. Once you have a good amount of tank water removed from the tank, it is best to take the time to clean and replace filter media. Spent tank water can be used to rinse sponges and pads free of debris; never use tap water for this process as it will kill much of the beneficial bacteria populating those surfaces. Some hobbyists choose to wait a day or two after they have performed a water change to clean and replace filter media; this way, all of the debris that had been kicked up does not go directly into a clean sponge.
  7. Stop siphon. Once you have cleaned the tank as much as you can (while not disturbing too much too fast), you may stop the siphon. Make sure to not leave your tank empty for too long as any areas that are exposed to air for too long will start to die off.
  8. Refill the tank. Once you have finished scrubbing the sides of the tank, vacuuming the substrate, wafting hard-to-reach places, and washing/replacing filter media, it is time to refill the tank with the water that you made. While betta fish should be able to withstand little changes in water conditions, it is best to go slow with this process. Make sure to double-check the temperature and gradually refill the tank with the remaining water. Once done, equipment may be turned back on.

The best time to do aquarium maintenance is during water changes. It is recommended to avoid putting your hands in the tank as much as possible otherwise, as each time that you do, you risk contamination and stressing out your livestock. However, if you’re struggling with algae, you might have to regularly reach within the tank at other times.

Note: Remember that betta fish are tropical fish and require tropical water temperatures. New aquarium water must match the temperature in the tank in order to not stress out your aquarium inhabitants. Room temperature water can really stress out your fish if it is too hot or too cold!

Also, remember that your heater will be unplugged while performing water changes so room temperature can start to affect the temperature of your tank depending on how long the process takes.

Products to avoid when cleaning your betta fish tank

All that water changes require is a way to remove and add water and de-chlorinate; no other chemicals are needed. However, when setting up a tank, most beginners want to clean their tank before they fill it up with water. Too many times, they use soap to clean the tank. Soap and detergent will inevitably lead to a dead betta fish.

Even small amounts of soap or detergent will affect your betta fish. In short, soap interferes with gill functions, leaving your fish to drown. This can happen very fast but is easily preventable. If you have an aquarium, or any other aquarium equipment or accessories, that you know has been in contact with soap, quickly remove up to 80% of the water and refill the tank; you want to dilute the soap as fast as you can. Repeat this process several more times; adding activated carbon may also help remove the soap.

When cleaning an established tank, it is always best to rinse as much as you can off with spent aquarium water. However, when starting a new tank, you may find yourself wanting to clean the tank before filling it with water. Luckily, there are a few products that are much less harmful than soap and just as easy to get.

Diluted white vinegar is a good alternative for cleaning most aquarium accessories and decorations. Simply mix a 1:1 of water and white vinegar and rinse and/or soak. Make sure to rinse the objects that were cleaned a couple of times to ensure that there is no vinegar residue; while unlikely if rinsed well, vinegar can also affect pH levels.

When in doubt, just use warm water. This is especially true for new setups where you are still able to dry off surfaces so that tap water doesn’t enter your system.

Note: Remember that this applies to any equipment that is also used to clean your aquarium, like the aquarium vacuum and any buckets!

Why is your betta fish tank so dirty?

There are a few reasons why you might find that your betta fish tank is especially dirty. Some of these possible causes are overfeeding, poor aquarium maintenance, and poor source water.


Betta fish are pretty easy to overfeed as they’re always willing to accept food. It is important to have a set routine with a set amount of food ready to go in order to prevent overlapping feedings. All food that is uneaten should be removed from the tank within a few minutes of feeding and food rationing should then be reconsidered.

Overfeeding can quickly lead to algae problems if left untreated. It is best to regularly clean the substrate and filter sponge/pad to make sure that food isn’t getting stuck and leaking nutrients.

Poor aquarium maintenance

Perhaps you are feeding your betta fish the recommended amount and there are little to no leftovers, but you don’t regularly clean your fish tank. As discussed before, lack of water changes will lead to nutrients, like nitrates and phosphates, quickly building up and leading to cloudy aquarium water, algae, or both.

Usually, cloudy water can be cleared up relatively quickly with water changes and a good deep cleaning, but sometimes a UV sterilizer is useful for larger tanks. Algae is more of a headache and will take several weeks to months to clear up; especially in a betta tank, natural solutions for algae removal can be difficult due to aggression.

Poor source of water

Maybe your problem doesn’t stem from overfeeding or poor aquarium maintenance; maybe your problem is at the source.

Tap water might be convenient and readily available to use for a fish tank for a betta, but it is not the best choice for the longevity of the tank. Tap water is usually filled with a lot of unknowns, from nitrates to heavy metals; the only way to definitively know what is in your tap water is by getting a laboratory test which can be quite expensive.

Reverse osmosis (RO) or distilled water helps remove most impurities from the water, helping prevent some future complications with parameters and possibly algae. So while your tank might not actually be cloudy from your betta fish, the source water is making it appear as though your tank is dirty.


Betta fish are relatively easy fish to take care of, but that doesn’t mean that they require any less maintenance than other tropical species. Before going out to buy your first fish, make sure that you know how to clean a betta fish tank and all the maintenance that goes into keeping your tank at optimal conditions.

If you have any questions about why you need to clean a betta fish tank, how to clean a betta fish tank, or have had experience with a particularly dirty betta, don’t hesitate to leave a comment below!

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