Do Betta Fish Need A Filter? The True Answer

    betta fish light schedule

    If it’s your first time setting up a Betta tank, it’s only natural to have plenty of questions in mind. And one of the most common questions asked by beginner Betta keepers is, “Do Betta fish need a filter?”

    In most cases, Betta fish do need a filter. Although these hardy, beautiful fishes can survive without one, they thrive better in a clean, stable tank environment that a filter can bring. So, to keep your Betta fish happy and healthy, it’s best to have a filter in your tank.

    This article will tell you everything you need to know about Betta fish and filters. If you want to become a better Betta fishkeeper, continue reading below.

    Do Betta Fish Need A Filter?

    Let’s get one thing out of the way first.

    Technically, Betta fishes don’t need a filter. What they need is clean, slow-moving, oxygenated water.

    If that can be achieved without a filter, then a filter isn’t necessary. That’s why heavily-planted tanks that are severely understocked can afford to not have a filter at all.

    That said, since this isn’t always easy to achieve, even for experienced fishkeepers, it’s highly recommended to still have a filter inside your Betta tank.

    In addition, if you have a large tank, say, a 20-gallon, with a single Betta, you can also get away with not having a filter since the water doesn’t get dirty as fast or as much. This is both beneficial to you and your Betta.

    In fact, many aquarists who keep their Betta in a filtered tank bigger than 15 gallons realize quickly that they only have to do 25%-30% water changes once every other week or even less. If they’re doing the Walstad method, they may not even have to do water changes at all.

    Smaller tanks, on the other hand, don’t have this luxury. Unfortunately, most people think Betta fishes can survive in tiny cups without a filter – or space to move, for that matter.

    However, that’s actually incorrect. While it’s true that wild Betta fish can spend short amounts of time in less than stellar conditions, like muddy water or shallow puddles, they don’t actually stay there for long. Bettas are prolific jumpers and would jump from one spot to another until they find an appropriate place to live and thrive.

    Sadly, captive Bettas are some of the most maltreated and misunderstood fish in the fishkeeping hobby.

    Since many people get their Bettas from pet stores that keep Bettas in small cups, they think that transferring them to a gallon or less of unfiltered water is already more than enough for this beautiful species.

    So, to circle back to our original question: do Betta fish really need a filter?

    The answer is simple. Betta fish need clean, stable water, and a filter is the easiest, fastest, and most convenient way to achieve that.

    Best Filters For Betta Fish

    can a filter kill a betta fish

    Now that we know that filters are beneficial for Betta fishes, how do you even choose a filter for them in the first place?

    In this section, we’ll discuss factors you should consider when getting a filter and the best filters for Betta fish you can get today.

    Factors to Consider

    Different filters have different purposes. Your Betta will benefit greatly if you can choose a filter that best suits them.

    Keep these considerations in mind before buying a filter for your Betta!

    • Bettas aren’t strong swimmers. In the wild, Bettas live in almost-stagnant bodies of water that are extremely slow-moving, if at all. Due to this, most Bettas are built to swim against the currents, especially if they have long, flowy fins. Be careful when choosing since Bettas need filters that don’t have a strong flow.
    • Betta fins can get sucked inside filters. It’s not unusual to hear people complain about their Betta’s beautiful fins getting sucked inside their filter. Bettas can be curious little fishes, and some may even enjoy hanging right outside their tank filter.
    • The filter should be sufficient for the tank size. Make sure you choose a filter that can sufficiently filter your tank. Remember, an underfiltered tank can be just as bad as an unfiltered one if it can’t even clean the water.

    Best Filters for Betta Fish

    Here are the best options when choosing a Betta filter.

    1. XINYOU Sponge Filter

    Sponge filters are an amazing addition to any Betta tank. For one, their outflows are generally much gentler than other types of filters, making them a great option for slow-swimming Bettas.

    The only downside to using a sponge filter is that you still have to buy a separate air pump for it. However, both sponge filters and air pumps are quite inexpensive, especially when compared to other types of filters.

    XINYOU, in particular, is a worthy pick since it offers plenty of different sizes for different tank capacities. Their smallest option is good enough for a 3-5 gallon tank, but they also have sizes suitable for larger Betta tanks.

    The sponge used is very soft, so even if you have a Betta who likes hanging out around the filter, there’s little to no chance that its fins will be hurt.

    In terms of cleaning, even beginners won’t have a hard time cleaning XINYOU sponge filters. Like other filters of this type, all you have to do is to squeeze it in dechlorinated water.

    However, if you’re doing water changes, it’s best to squeeze this filter in a container filled with water from your own tank to make sure the beneficial bacteria won’t be killed in the process.

    The only possible downside to using XINYOU filters, or sponge filters in general, is that they can be quite unpleasant to the eye. Of course, this still depends on your preference, but many aquarists don’t like how it looks like inside their tank.

    If you’re one of these people, though, you can try putting it at the very back of your tank and covering it with decor.

    2. Fluval 206 External Filter

    The Fluval 206 External Filter is an all-around canister filter that can fit tanks that are as large as 45 gallons. This is more than enough for most Betta tanks.

    Although it’s much more expensive than the previous sponge filter, it does feature different types of filtration, namely biological, mechanical, and chemical.

    If you want to customize the types of filtration this filter has, you can do so easily and quickly. Fluval offers plenty of media options for this filter, so you can switch out any media for whatever you want. Even the media for biological and chemical filtration are separated.

    Another positive thing about this is how quiet it is. Some filters make a lot of noise when working. While the Fluval 206 isn’t exactly silent, it is quiet enough to not be bothersome even in a quiet room.

    That said, the flow can be quite strong, especially if your tank isn’t that large. You may have to install a baffle in order to prevent it from making the current in your tank too strong for your Betta to swim comfortably.

    Overall, though, the biggest downside of the Fluval 206 External Filter is the price. If you have the money to spend for your Betta-keeping hobby, though, you can’t go wrong with this filter.

    3. AquaClear Power Filter

    If you want a Hang On Back (HOB) filter, the AquaClear Power Filter is a great choice.

    One of the main reasons why people want HOB filters is that they don’t detract from the view inside the tank. Since it’s installed at the back or side of the tank, the only thing you’ll be seeing of it is the hose and the upper part of the HOB filter.

    This is also true for the AquaClear Power Filter. Aside from being aesthetically pleasing, it’s also suitable for tanks up to 20 gallons. If you have tanks of other sizes, you can check out other AquaClear Power Filter capacities to find the one most suitable for your tank.

    In addition to that, you can control the flow rates on the AquaClear Power Filter. This is very beneficial in case your Betta fish has particularly large fins and doesn’t enjoy strong currents.

    Also, it features a re-filtration system. The water gets filtered and refiltered multiple times, which means you can make sure that the water can remain crystal clear with this type of feature.

    You can also use mechanical, chemical, and biological filtration options with this filter. The media can be switched out and changed into something else you prefer, although it does come with default AquaClear products.

    4. Azoo Mignon Filter 60

    The Azoo Mignon Filter 60 is a great filter for Betta tanks that are less than 10 gallons.

    It’s a clear HOB filter, which means it blends well at the back of your tank. The flow rate is also adjustable, so you can change it up depending on your Betta’s needs.

    In terms of noise, it’s a lot quieter than other similar filters on the market. You probably won’t even notice it unless you really try to listen. Make sure you attach the black knob that’s included in the package to keep the vibrations to a minimum.

    Best of all, it comes with a prefilter when you buy it, which prevents your fish from being sucked in. This is great if you have a curious little Betta since you don’t have to worry about them accidentally getting injured by the filter.

    The only issue is the unsatisfactory filter media that comes with it – but you can always replace this with something better.

    5. Aqueon QuietFlow Internal Power Filter

    This internal filter is fully submersible and can be placed either vertically or horizontally inside the tank. It can use the three stages of filtration: biological, chemical, and mechanical.

    Its outflow nozzle is also adjustable and extendable, which means you can customize your flows. The flow rate itself can’t be adjusted, however.

    Despite its name, it’s not as quiet as the previous filter on this list, but it is much quieter than other filters of its type. It emits a soft humming sound, not loud enough to bother anyone. Just don’t expect it to be silent and you should be good.

    For the price though, it’s a solid filter that should be powerful enough for your Betta tank.


    Benefits Of Having A Filter In A Betta Fish Tank

    Betta Fish Filter Benefits

    If you’ve gotten this far, you probably already know this by now, but there are plenty of benefits to having a filter in a Betta fish tank.

    • Keeps the water clean. This is perhaps the biggest reason why having a filter is beneficial to any Betta tank. A filter’s main purpose is to clean the water, which should be your top priority if you want to keep fish.
    • Minimizes toxins in the water. Speaking of cleaning, you know those things called ammonia, nitrites, and nitrates? Too much of those can seriously harm your fish, sometimes even enough to lead to their death. Filters can help minimize the toxins in the water, making it safe for your Betta to live in.
    • Helps with water circulation. Stagnant water can become a breeding ground for bad bacteria. By using a filter, even one with the most gentle flow, you’re preventing the water from ever becoming stagnant.
    • Houses beneficial bacteria. If you’re familiar with cycling, you should also know how important it is to have beneficial bacteria in your tank. These bacteria help keep toxins in your tank to a minimum. A few live in the water column, but most live on the surfaces of your filter, gravel, and even hardscape.
    • Oxygenates the tank. Although Bettas have a labyrinth organ that allows them to breathe air from the surface, it’s still best for your fish’s health if the water is oxygenated. In fact, when oxygen in the water is low, your Betta can become lethargic and weak. This is why most Bettas in small bowls don’t seem to move at all – due to the lack of oxygen.
    • Makes maintenance easier. Last but certainly not least, having a filter in your tank also makes maintenance easier. After all, if your water is crystal clear and there are hardly any toxins, you don’t have to do as many water changes. You can probably get away with just changing a quarter of your water every week or two with no issues. The removal of nitrogenous waste by filters also keeps algae, fungi, and biofilms down to a minimum.

    What Does A Filter Do?

    How a filter works exactly depends on its specific type. For instance, a sponge filter works differently from a canister filter, and HOB filters work differently from internal filters.

    The basic principle sticks, though: as water passes through or by the filter, its filter media cleans or purifies the water.

    Additionally, you also have to consider the type of filtration that a filter can do. Here are the three types of filtration in an aquarium tank.

    • Mechanical filtration. The simplest type of filtration. As the name implies, this type of filtration physically removes dirt and debris from your tank. Of course, you still have to clean the filter media every now and then to remove everything that stuck to the filter. Examples include sponges, filter floss pads, and filter socks.
    • Biological filtration. Remember those beneficial bacteria that we mentioned earlier? This type of filtration uses those bacteria in order to remove toxins from your water. Some examples are bio-media like bio-rings and bio balls that have enough surface area for beneficial bacteria to thrive.
    • Chemical filtration. To remove waste from your water, this type of filtration typically uses media that can remove chemicals, impurities, and even medications from your water. This is usually done by using special resins or activated carbon.

    You can typically find two or even three types of filtration in one filter. Even the simplest type of filter, sponge filters, can have bio-media inside it for additional biological filtration.

    Here are the main types of filters that you’ll see in a regular Betta tank.

    • Sponge filter. Many Betta owners opt for sponge filters for one simple reason: they’re completely safe for these beautiful little fish. They’re also inexpensive and straightforward to use, making them easy to deal with for beginner owners. Their main mode of filtration is mechanical, although, as previously mentioned, you can also add bio-media for biological filtration.
    • HOB filter. HOB stands for “Hang on Back.” This type of aquarium filter got its name from the way that it’s usually hung on the back of tanks – though you can also hang it from the side if you want to. It’s a very popular type of filter since it features all three types of filtration methods. HOB filters are also easy to maintain since accessing them takes seconds.The only downside is that they’re typically a lot more expensive than a basic sponge filter and air pump combo.
    • Canister filter. If your Betta is in a community tank that’s at least 40 gallons, you may want to consider a canister filter. These are powerful filters that are strong enough to actually push water into the filter media using pressure. Make sure that you don’t use this in a small tank, as it can be way too strong for your Betta to handle. Canister filters are the kinds of customization. They have huge media chambers that even HOB filters can’t match.
    • Internal filter. Also known as box filters or corner filters, internal filters usually contain different filter media in order to keep the water clean. Many internal filters work the same way as sponge filters and need an air pump in order to have some kind of flow.

    There are also other types of filters like under-the-gravel filters (UGF) and trickle filters, but they’re not typically used for Betta tanks due to their size and power.

    What Would Happen If A Betta Fish Tank Does Not Have A Filter?

    betta fish filter

    Assuming that your tank isn’t planted or is sparsely planted, there are two things that can happen if your Betta tank doesn’t have a filter.

    First, your tank will look–and even smell–noticeably dirtier. Without anything to filter your water, all the waste, dirt, debris, and toxin will just build up in your tank. You’ll have to do frequent water changes in order to keep the environment safe for your fish.

    Some Betta keepers with small, unfiltered tanks realize soon enough that they have to change the water every two to three days just to prevent their Betta from getting sick.

    However, doing so can put a lot of stress on your Betta. Water changes, especially if done frequently, cause stress. Over time, all this stress can lead to common Betta diseases and problems, such as Betta fish turning white or losing color.

    Two, your Betta’s lifespan can take a hit. In captivity, Betta fishes typically survive for 3-5 years, but if their water conditions are perpetually bad, they may only live for a year or even less.

    You may have heard of a friend of a friend’s Betta fish living for years inside a tiny, unfiltered bowl, but trust us – they’re the exception, not the rule. Bettas are naturally hardy fishes, so they may have just gotten an extra hardy individual.

    Besides, you have to remember that surviving is not thriving. Just because a Betta fish lived for years in bad conditions doesn’t mean that it lived a happy life.

    Betta Fish Tank Requirements

    We’ve discussed how important water conditions are when it comes to taking care of fish, specifically Bettas. But what exactly are the tank requirements when keeping a Betta?

    Tank Size

    Betta fishes should be kept in tanks that are at least 3-5 gallons. Some aquarists even recommend keeping them in no less than 10 gallons.

    Thus, it’s safe to say that 5 gallons is the ideal minimum, although there are also slower-moving varieties that don’t mind living in filtered and heated 3-gallon tanks.

    However, you have to understand that, like other fish, Bettas still do best in larger tank environments. They also enjoy having plenty of plants and hiding spaces – and you can do this much better if you have the real estate to do so.

    Water Parameters

    Although Bettas are very hardy fish, they fare much better if their ideal water parameters are met.

    pH 6.8-8.5
    Temperature 75F-82F
    Ammonia 0 ppm
    Nitrite 0 ppm
    Nitrate <20 ppm
    GH 3-4 dGH
    KH 3-5 dKH


    Can A Filter Kill A Betta Fish?

    Unless the filter is super strong, it’s unlikely to kill your fish. However, it’s not unusual to hear stories of Betta fins getting torn up by a filter that’s way too strong.

    A sick or old betta fish may also struggle with the flow of a power filter. A sponge filter is better for a weaker fish.

    Do Betta Fish Need A Heater?

    Bettas are tropical fish, so they need to stay in an environment that’s 76F to 82F. If you live in a naturally hot climate, you can perhaps get away without a heater.

    Bettas are chill tolerant. But prolonged periods of cold weakens their immune systems and shortens their lifespans.

    However, if you live in the US, for instance, where the temperature can change drastically depending on the seasons, it’s critical to have a heater in your Betta tank.

    Do Betta Fish Need A Light?

    Betta fish need light in the aquarium, especially if you’re keeping them in a room that doesn’t have windows. In the wild, Bettas use the sun to establish their body’s sleep cycle.

    Since they’re naturally diurnal, they need to have a period when it’s dark to signal that it’s time for them to sleep, as well as a period when it’s bright for them to move around.

    What Size Tank Does A Betta Fish Need?

    The ideal tank size for a Betta fish is 5-10 gallons, although they can’t be kept in aquariums as little as 3 gallons. Anything smaller than this is unhealthy for your Betta fish, as well as difficult to maintain and keep stable.


    Bettas are extremely hardy fish that can survive for short periods in bad environments and poor conditions. However, if you really want your Betta to thrive and live a long time, make sure you do your due diligence in preparing their tank. This includes adding a filter.

    Of course, filters are not always necessary, especially if you have a large, densely planted tank. For most tanks, though, it’s a safe choice.

    So, to answer your question of “do Betta fish really need a filter?” we’ll repeat what we said at the beginning of this article: Bettas may not need a filter, but they do need clean water and a filter is the easiest way to make sure you achieve that.

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