Clean a Betta Fish Tank

How Often Do You Clean a Betta Fish Tank?

One of the major differences between bettas and dogs is that most people do their care research after getting the betta but before getting their dog. We all have some basic idea of how to care for them, I mean, you just put them in water, right? Unfortunately, it is not always that easy. The good news is your betta is easier to take care of than your dog, but you still have to clean up after it.

In terms of cleaning up after your betta, there are several ways to go about this. The best way is to do a water change using a gravel vacuum, which we will discuss further. While the rate of water changes should be based on how many nitrates you have, the general rule is 25%-50% once a week. If you have only your betta in a 5 or 10 gallon, a 25% once a week is perfect.

In this article, we will discuss the nitrogen cycle, weekly water changes, mineral replacement, algae, gravel vacuuming, cleaning the filter, and cleaning decorations.

Nitrogen Cycle

The nitrogen cycle is a vital part of fish keeping, and unfortunately, most people starting out are unaware of it. Unlike a dog who just uses the bathroom in the yard and runs back inside, a betta fish is stuck in close proximity to its waste.

One issue with your fish living in water is that things decompose very quickly. A small fish body may be entirely gone in a few days to a few weeks, and their waste disappears rapidly as well, but it doesn’t just disappear…

Fish waste breaks down into ammonia, which is a highly toxic nitrogen compound. Ammonia often causes severe damage to the gills and black burns across the body. It can burn off the fins and scales of the fish.

One to two weeks after ammonia levels climb, a little bacterium comes along converts ammonia to nitrite, another nitrogen compound. Nitrite is even more lethal. It binds to hemoglobin in the blood and prevents it from carrying oxygen, suffocating the fish.

Another two or so weeks after that, nitrite turns into nitrate, which is much less harmful. The whole cycling process takes about a month on average.

It takes this long because the bacteria that turn ammonia to nitrite can’t live without the ammonia food source. Therefore, they don’t have high numbers until a fish is added. After they get their food source, it takes time to build a colony large enough to convert all ammonia very quickly.

The same goes for the other bacterium; they can’t start growing until the first bacteria starts producing enough nitrite.

Ammonia and nitrite are toxic at every level, even just 0.25ppm. On the other hand, nitrates are tolerable up to 20ppm.

Weekly Water Changes

Weekly water changes are primarily used in order to keep nitrates at a safe level. These are only used after your cycle is complete, because during the cycle, you normally must do daily water changes to keep the ammonia and nitrite as low as possible.

Even just a little bit of ammonia or nitrite will shorten your fish’s life span. In addition, they are fully capable of feeling pain, and constantly being burned and/or suffocated is not humane.

If you have your betta in a community tank, you will have to monitor your nitrates to tell when you should change your water. Once they hit right below 20ppm, you need to change your water.

If you have just singular betta in an appropriately sized tank (5-10 gallons), a 25% water change once a week will keep your little buddy nice and happy and your nitrates low. High nitrates ruin the immune system of your fish, so even though they appear healthy on the outside, they could be ill on the inside.

Mineral Replacement

The second reason for water changes isn’t as well known. In fact, this is the primary reason for water changes on tanks that have 0 nitrates (normally from many plants or bacteria that convert nitrates to nitrogen gas).

Even if there are no nitrates present, it is important to change the water in order to both replenish minerals and keep them low. Fish take in some of their needed minerals from the water around them, not just their food as we do.

Without water changes, they will run out of necessary minerals and could suffer deficiencies. In addition, since bettas live in heated tanks, the water evaporates rather quickly.

The evaporated water carries away very little minerals, but the water left behind condenses these. Over time, if you only top off the missing water during water changes or throughout the week, the amount of minerals will build excessively.

This can lead to Old Tank Syndrome and to your tank crashing, so it is well worth the weekly water changes. Lowering pH and rising TDS (total dissolved solids) are warning signs of Old Tank Syndrome right before the tank crashes and kill fish.


If you are battling an algae problem, chances are you have excess nitrogen compounds. Algae, like every other organism, needs nitrogen to live. Algae obtain nitrogen through ammonia, nitrite, and nitrate.

If you starve it of its nitrogen, it will be unable to grow as quickly, or at all, but will not all die off. To ease your battle against algae, simply do some extra water changes. That takes out minerals and nutrients it needs and will make it easier for you to defeat.

Gravel Vacuuming

The gravel vacuum can be used on gravel, sand, and bare bottomed tanks, but the use is slightly different for each. It is essentially one large, rigid tube connected to smaller flexible tubing. The large tube can be plunged into the gravel, swept along a bare tank, or twirled just above a sand bed to lift waste and take it out.

The best way to use these is to drain them into a bucket then dump the bucket into a sink or tub (or a garden, best fertilizer ever!). If you don’t use a gravel vacuum, waste in the substrate will continue to build up and you will constantly struggle against high nitrates.

Be careful when using these, as some bettas will be drawn to the particulates they see moving up the tube and may try to get some. It is possible for bettas to become severely injured or even die if they get swept up into one. At the worst, they can become lodged inside.

That being said, gravel vacuums are essential to taking care of your tank, so you just need to be careful when using one. I have personally never had a problem, as most of my bettas are too lazy to chase down their food.

Cleaning the Filter

Cleaning your filter is another necessity for weekly tank maintenance. Similar to gravel vacuuming your tank, cleaning the filter removes mulm and debris that lead to increased nitrates. However, you must be very careful when cleaning your filter as it houses over 90% of the bacteria that keep your cycle.

Removing the filter pad and throwing it out or rinsing it under the tap water are big no nos. This will destroy your cycle and you’ll have to do daily water changes for another month. The bacteria are sensitive to chlorine in the tap water, which is why you can’t rinse it, and throwing out the pad removes the bacteria.

On the directions of most filter pads, it states that you should remove them after one month. This is due to the activated carbon inside that expires after about a month. The activated carbon is not necessary for aquariums and can actually become a problem.

If you have a planted tank or must dose medications, the carbon will be an issue. It absorbs fertilizers and medications, which makes it great for removing medications, but bad for using medications. You can simply cut a slit in the filter pad and pull out the carbon when you don’t need it.

Cleaning the filter depends on the type of filter you have. If you have a sponge filter, remove the sponges and squeeze them several times in a bucket of old tank water, then replace them. The same goes for the media in H.O.B. filters, but you also need to take out the impeller and clean gunk off of it.

Cleaning Decorations

Cleaning decorations are luckily very simple and easy. Some beneficial bacteria live on them, but the amount is so small that it’s fine to kill them. Be sure to remove decorations regularly to clean the substrate under them, but weekly cleaning is not necessary.

If you feel that your decorations are looking a little on the rough side, buy a new toothbrush, remove the decoration, and scrub off whatever is bothering you. Most soft algae will come off very easily, and you can rinse the decoration under tap water as well.

However, you must dry off the decoration completely before replacing it in the tank, as the chlorine can damage the other bacteria in the tank.

In conclusion, you should change your betta’s water weekly as well as do other weekly maintenance. This includes cleaning the filter media, vacuuming the substrate, and testing your water parameters. Bettas are very easy to take care of since they only require weekly cleaning, unlike a dog or a cat.

Leave a Comment