How Big Should A Betta Fish Tank Be? 5 Factors To Consider

    How big should a betta fish tank be

    If you’re like any serious fishkeeper, then you love your betta fish. They are so beautiful and colorful! But if you want to keep your betta happy and healthy, you need to give him the right environment. So how big should a betta fish tank be?

    The answer to that question depends on a few factors, such as the size of your Betta fish, the Betta variant you have, and whether you intend to keep other fish with your Betta. But in general, a Betta fish tank is recommended to be at least 5 gallons to be on the safe side, and preferably 10 gallons if you’ve got the space for it.

    In this article, we’ll go over all the factors you need to consider when deciding how big your Betta fish tank should be so that you can give your fish the best possible home.

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    How Big Should A Betta Fish Tank Be? Best Tank Size For Betta Fish

    how big should a betta tank be

    Betta fish, also known as Siamese fighting fish, are a popular choice for aquariums because of their bright colors and interesting personalities.

    Bettas are a type of freshwater fish that come from the tropical waters of Southeast Asia.

    In the wild, bettas live in small ponds and puddles as their natural habitat, where they hunt for food and build bubble nests. But in captivity, bettas are often kept in small bowls or fish tanks that are too small for them.

    While bettas may seem like tiny fish that can technically survive in small Betta tanks, they will not thrive. A small tank is more likely to cause health problems for your betta than bigger tanks.

    So, how big should a betta fish tank be?

    The bare minimum tank size for a betta fish is 2.5 gallons, but this is only suitable for a very small fish or if you do not plan to keep any other fish with your betta.

    A better size for a betta fish tank is 5 gallons, which will give your fish enough room to swim and be active.

    Of course, if you want your Betta to have tankmates, then you will need an even larger tank. The bigger your tank, the more you can house. A 10 gallon tank is a good size for a community fish tank with a Betta and other invertebrates.

    The ideal tank size for a betta fish is 20 gallons, but this may not be practical for everyone. If you have the space for it, though, a larger tank is always better.

    When deciding how big to make your betta fish tank, remember that it is better to err on the side of too much space rather than too little. A larger tank will provide a more stable environment for your fish and will give them more room to swim around and explore.

    5 Factors to Consider When Choosing Betta Tank Size

    Now that we’ve answered the question of how big should a betta fish tank be, let’s go over some of the factors you need to consider when deciding on a tank size for your betta.

    1. The Size Of Your Betta Fish

    Bettas come in a variety of sizes, from the tiny micro bettas that only grow to be an inch long to the giant bettas that can reach up to 4 inches in length. Obviously, the size of your Betta fish will be a major factor in determining the appropriate tank size.

    A small Betta fish can get by in a 2.5 gallon tank, but a larger Betta will need at least a 5 gallon tank at the very minimum. If you plan to keep more than one Betta fish, you will need an even larger tank.

    2. The Variant Of Your Betta Fish

    There are many, many Betta fish variants out there. The most common and iconic Betta fish variant is the halfmoon Betta, which has a long, beautiful tail that flares out to form a half-circle shape.

    But there are also other variants like the crowntail Betta, which has a spiky tail, and the plakat Betta, which has a shorter body and even shorter fins.

    The type of Betta you have will also affect the appropriate tank size. Some variants, like the halfmoon Betta, tend to swim slowly, so they can be perfectly happy in a 5 gallon tank.

    Meanwhile, plakat Bettas, with their short fins, can swim very quickly over long distances.

    If you have a plakat Betta, you might want to consider getting a 10-gallon or a 20-gallon long to give them space to zoom around the tank.

    3. The Number Of Tankmates

    If you plan on keeping other fish with your single Betta, then you will need a bigger tank.

    Bettas are territorial fish, and they will not do well in close quarters with other fish. They need to have space to breathe and to establish their own territory.

    Additionally, you need to account for their bioload as well.

    If you want tankmates, such as shrimps, snails, and other small peaceful fish, then you need at least a 10-gallon tank. If you want to keep multiple Bettas together, then you will need an even bigger tank.

    4. The Type Of Tank

    The type of tank you choose will also affect the appropriate tank size for your Betta fish. For example, a bowl-shaped tank might look cute, but it is not the best type of tank for a Betta fish. Bowls do not give Bettas enough space to swim around, and they can be very difficult to clean.

    A better option for a Betta fish tank is a rectangular tank. This type of tank gives Bettas more space to swim, and it is also easier to clean. If you choose a rectangular tank, make sure it is at least 10 gallons. Also, the longer the better, as Bettas love to swim back and forth.

    5. Your Budget

    Of course, the size of your budget will also be a major factor in deciding on the appropriate tank size for your Betta fish. If you can afford a 20-gallon tank, then that is the best option for your Betta. But if you can only afford a 5-gallon tank, then that is better than nothing.

    You can always upgrade to a larger tank later on, so don’t feel like you have to get the biggest tank right away. Just start with something that is big enough for your Betta and upgrade when you can.

    Minimum Betta Fish Tank Size

    minimum betta fish tank size

    As mentioned above, there are some fishkeepers who believe that 2.5 gallons is the bare minimum size for a Betta tank.

    However, this could be quite limiting for your Betta, especially if you have a short-finned variant. Short-finned variants, like the plakat Betta, are very active and need a lot of space to swim.

    We recommend getting a 5-gallon tank at the very minimum, and, if you have the budget for it, a 10-gallon tank. This will give your Betta the space it needs to swim around and be happy while keeping the bioload low. Plus, it will allow you to add more hiding places, which Bettas love.

    Maximum Betta Fish Tank Size

    how long do betta fish live in a tank

    There is no maximum size for a Betta fish tank. Bettas can be kept in tanks as large as you have the space and budget for. In fact, if you want to keep your Betta in a 50-gallon tank all by itself, then there’s absolutely no problem with that.

    Some people believe that Bettas should only be kept in small tanks because they are “small fish.” However, this is not true. Bettas are actually quite large compared to other “small” fishes like guppies and mollies, and they need a lot of space to wander around.

    The only time you might not want to get a very large tank for your Betta is if you have a long-finned Betta. Long-finned Bettas can’t swim as well as short-finned varieties, so they prefer a shallower but longer tank to a bigger but deeper tank.

    What’s Better For Bettas: A Big Fish Tank Or A Small Fish Tank?

    There’s no debate that larger tanks are better for Bettas. Bettas need space to swim around, and a larger tank gives them more room to do so.

    Additionally, a bigger tank is easier to maintain than a smaller one because you don’t have to make water changes as frequently. The bioload is also lower in larger tanks, which means there is less chance of your Betta getting sick.

    However, that doesn’t mean that you shouldn’t get a small tank for your Betta if that’s all you can afford. A 5-gallon tank is better than a 2.5 gallon and your Betta will still be able to swim around.

    Best Betta Fish Tanks By Gallon

    Best betta fish tanks by gallon

    Wondering which tank size is best for your Betta? Here’s a rundown of the best Betta fish tanks by gallon!

    2.5 gallons


    • Small enough to fit anywhere in your home
    • Gives Bettas space to swim


    • Not recommended by most serious Betta fishkeepers

    If you must go with a 2.5 gallon tank, then make sure it is at least 12 inches long. There are many 2.5 gallon options out there, but not all of them have this configuration. Some are even more square than rectangular. A tank with 15 inches of length will give your Betta enough space to swim around a bit.

    The best 2.5 gallon tank you can buy is the Petmily Small Fish Tank Aquarium Kit. Like its name implies, it’s a complete kit that comes with its own filter and lighting. It’s also 15 inches long, which is perfect for Betta fishes.

    5 gallons


    • Much better than a 2.5 gallon tank
    • Enough space for most Bettas to swim


    • Still not enough for active or short-finned Bettas

    A 5 gallon tank is the minimum size we recommend for Bettas. It’s much more spacious than a 2.5 gallon tank and gives your Betta enough space to swim around.

    The best 5 gallon tank is the Tetra Crescent Aquarium Kit. It comes with a filter, lighting, and everything else you need to get started. It even comes with a curved glass design (although it’s made from acrylic), allowing you to see your Betta fish better in all more directions.

    Not to mention, with a length of almost 17 inches long, this tank can give your Betta more freedom to swim and explore.

    10 gallons


    • The ideal size for most Betta varieties
    • Large enough for even short-finned Bettas


    • More expensive than smaller tanks

    If you’re a beginner in the fishkeeping industry, a 10 gallon tank is the best size for a Betta fish. It’s large enough to give your Betta plenty of space to swim around and explore, but not so large that it’s difficult to maintain.

    The best 10 gallon tank on the market is the Aqueon Aquarium Starter Kit. This tank was made specifically with beginners in mind. It comes with a filter, lighting, and all the other necessary accessories to get started. All you need to do is add water and fish!

    20 gallons


    • The ideal size for short-finned Bettas
    • Large enough for active Bettas


    • More expensive than smaller tanks

    A 20 gallon tank is the perfect size for a short-finned Betta. Just like the 10-gallon tank, it’s large enough for any Betta to swim around as they please, but it’s still relatively easy to maintain.

    There are also many options out there for 20-gallon tanks, but our personal favorite is the Tetra 20 Gallon Fish Tank Kit, which has a sleek and modern design. This tank also comes with a filter, lighting, and everything else you need in a beginner fish tank.

    20-gallon long


    • Best for Bettas with invertebrate tankmates
    • Enough space for any Betta to swim


    • Can be very expensive
    • Needs a large area

    One popular variant of the 20-gallon is the 20-gallon long tank. As you can probably guess, this tank is longer than it is tall, giving your Betta even more swimming room.

    While a 20-gallon long tank is a perfect size for a Betta fish, it can be very expensive. Not to mention, you’ll need a large area to put it in since it’s much longer than a standard 20-gallon tank. In fact, our top pick, the Tetra Aquatic Deluxe Kit is almost 34 inches long. It’s made specially for turtles, but you can also use it as a Betta fish tank.

    How To Set Up A Betta Fish Tank

    How to set up a betta fish tank

    Now that you know what size tank is best for your Betta, it’s time to set it up! Here’s everything you need to do to get your Betta fish tank ready for your new pet.

    Equipment Needed

    You need to get the right equipment to put in your Betta fish tank. Here’s a list of everything you’ll need to get started.

    A Water Conditioner

    A water conditioner is an essential piece of equipment for any Betta fish tank. It removes harmful chemicals from the water that could harm your Betta. Be sure to use a water conditioner every time you change the water in your tank. Our best recommendation is the Seachem Prime Conditioner, but there are also plenty of other options, like the Aqueon Aquarium Fish Tank Water Conditioner and the Tetra AquaSafe Plus Water Conditioner.

    A Filter

    A filter is another essential piece of equipment for a Betta fish tank. It helps to keep the water clean and clear by removing debris and waste from the water. There are many different types of filters available, so select one that is appropriate for the size of your tank.

    A Heater

    A heater is necessary if you want to keep your Betta tank at a consistent temperature. Bettas are tropical fish and need warm water to thrive. Choose a heater that is appropriate for the size of your tank. Here are some of our best picks:

    A Thermometer

    A thermometer is essential for monitoring the temperature of your Betta fish tank. Be sure to check the temperature of your tank regularly to make sure it is within the appropriate range for Bettas.


    Substrate is necessary for the bottom of your Betta fish tank, most importantly if you want to add live plants. Be sure to choose substrate that won’t harm your Betta in any way, such as gravel or sand.


    Plants are not necessary for a Betta fish tank, but they can provide shelter and hiding places for your Betta. Be sure to choose plants that are safe for Bettas and that will not harm your fish if they eat them.


    Just like plants, decorations are not necessary for a Betta fish tank. However, they can help to make your tank more visually appealing as well as be more comfortable for your fish. If you want something that’s simple but effective, you can put a betta hammock or a betta leaf in your aquarium.

    How To Set Up The Tank

    Here are the steps you need to follow to set up your Betta fish tank.

    1. Choose The Right Location

    The first thing you need to do is choose the right location for your Betta fish tank. It should be in a place where it won’t be in direct sunlight and where it won’t be too close to any electrical outlets.

    2. Sanitize The New Tank

    Once you’ve chosen the perfect location for your Betta fish tank, it’s time to sanitize it. After all, just because it came fresh from your local pet stores or online stores doesn’t mean it’s completely clean. It may still have some harmful bacteria in it that could be dangerous to your Betta.

    You can sanitize it by wiping down the inside of the tank with a diluted bleach solution. Be sure to rinse the tank thoroughly afterward in order to remove any traces of bleach.

    3. Add The Substrate

    The next step is to add the substrate to your Betta fish tank. Substrate helps to keep the water clean and provides a place for beneficial bacteria to grow. It also makes your tank look more attractive.

    Plus, if you have live plants, you’re definitely going to need nutrient-rich substrate to grow your plants. We recommend using tried-and-tested substrates like ADA Amazonia and Fluval Plant and Shrimp Stratum.

    The amount of substrate you need depends on the size of your tank. To know how much substrate you should add to your tank, you can use an online substrate calculator like this one.

    4. Install The Filter

    Now it’s time to install the filter in your Betta fish tank. As mentioned above, your filter should also depend on the size of your tank. If you have a smaller tank, a simple sponge filter should do. However, if you have a bigger tank, you might need a more powerful filter.

    4. Fill The Tank With Water

    Now it’s time to fill up your Betta fish tank with water. You can use tap water, but be sure to treat it with a water conditioner first. This will remove any harmful chemicals from the water that could harm your Betta.

    5. Add The Decorations

    The last step is to add the decorations to your Betta fish tank. This is where you can get creative and make your tank look however you want. Just be sure to avoid anything that could sharp edges that could hurt your Betta.

    Now that you know how to set up a Betta fish tank, it’s time to choose your Betta and add them into their new home.

    Ideal Water Parameters For A Betta Fish Tank

    Regardless of your tank size, there are certain water parameters that you should always maintain in your Betta fish tank.

    Scientific Name: Betta splendens
    Size: 2 to 4 inches
    Number in a 5-Gallon Tank: 1
    Diet: Omnivore
    Temperament: Aggressive
    Lifespan: 2 to 5 years
    Temperature: 78°-80°F or 25.5°- 26.5°C
    pH: 6.5 to 7.5



    When it comes to Betta fish care, there are many things that we can learn every day.

    For instance, although bigger is always better, we understand that not everyone has the space for a giant tank. So, if you’re like most people and don’t have a lot of extra space in your house but still want a betta (or two), don’t worry – 5 gallons is the bare minimum for your first Betta tank. Remember to add plenty of hiding spots to make your fish feel at home and lead a healthy life!

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