How Big Should a Betta Fish Tank Be? Tips for New Owners

Author Image

By Alexandra Miller

Updated: Mar 24, 2025

8 min read

Betta Fish Tank Size
AI Generated Image: Heaven Gables

Table of Content

    “What tank do I require for betta fish?” It is one of the most commonly asked questions, especially by homeowners buying betta aquariums for the first time. You’ll find varying answers to the question with a whole lot of information. Some believe they can be kept in a small cup or a 1-gallon tank, which is not true. Betta fish cannot survive in such a tiny space, which harms them. Your betta fish deserve better because these tropical fish come with certain considerations regarding tank size and neighbors. So, we are here to tell you the exact tank size depending on the number of betta fish you have.

    Betta Fish Overview

    Betta fish, also known as Betta Splendens, originate in the tropical waters of Thailand and Southeast Asia.

    • They are calm and slow-moving fish who love to dwell in stagnant water.

    • These fish love to thrive in densely vegetated shallow water bodies.

    • They usually repel other fish from the habitat to maintain their way of life.

    Fun Fact: Prussian Carp are the ancestors of Betta fish, who were bred for their large size and wholesome meat. With time, people started keeping them as pets, mostly because of their vibrant colors and intricate fin shape. Today, Japan breeds this fish, which we know as Koi fish.

    Characteristics of Betta Fish

    Difficulty Of Care Beginner

    Average Life Span 3-5 years with proper care

    Average Adult Size 2.5 inches long (tail excluded)

    Diet Carnivorous

    Minimum Habitat Size 1 Gallons or more

    Water Temperature 72-82 F

    pH 6.0-8.0

    What Tank Size Do Betta Fish Need?

    Betta Fish Tank
    AI Generated Image: Heaven Gables

    There is a major misconception, as said above, that betta fish love tiny and enclosed spaces. Well, most fish experts recommend 5 US Gallons. However, if you are a beginner, it is recommended to have a betta tank size of 30 liters/8 US Gallons/6.5 Imperial Gallons. It is important to meet this minimum standard to keep your pet betta happy and unstressful. Also, the RSPCA recommends using 4 - 5.3 Gallons as optimal.

    As a new betta enthusiast, you will be overwhelmed by over a thousand fry, which will grow and mature soon. Hence, a tank 5-gallon size is better, as you don’t have to worry about the Betta getting sick or, worse - dying. Also, you can be stress-free about not having a tank changed occasionally.

    Plakat bettas can thrive in a smaller or larger tank. At the same time, some giant bettas do well in larger tanks. They use all the space, which is beneficial for their well-being. However, the long-finned dumbos often rest more and can do well in a 3-gallon long tank.

    Bettas are considered hardy fish, meaning most people may mistake them to be happy in a confined space. But in reality, small spaces make them ill. They are smart fish; hence, they need bigger space to swim. So, if you’re considering keeping the Betta in a bowl, you must think again and harder.

    Factors to Consider Before Buying Betta Fish Tank

    Here are certain major factors that must be considered, especially if you’re a new betta parent:

    The Shape of the Tank

    Not all tank shapes are equal. The shape may not be appropriate even if you have the Betta in a standard 5-gallon tank. Taller tanks are not a very good place for Betta to survive. As we already know, bettas love to dwell in shallow waters and swim left and right.

    Hence, a tank with more depth gives them smaller space. It is advisable to pick a longer tank to give the bettas more space to swim naturally.

    Space Inside the Tank

    Setting up a tank is fun! However, it is important to consider that the ornaments may take up space. If you have a small tank, it won’t leave much space for the bettas to swim properly. Decorations do not include essentials such as filters, heaters, gravel, etc.

    Remember, whatever you put in the tank takes up space. So, if you plan to decorate the tank, consider smaller and minimal ornaments so there is enough space for the heaters and filters to fit in. Always leave maximum swim space for a betta to explore the tank.

    Consider a Tank With Lids

    Betta fish can jump. Though they are smart and intelligent, they may not know there is no water on the other side of the tank and may think of diving into the other side. No wonder they are calm but can quickly jump out of the tank.

    Hence, it is advisable to get an aquarium with lids. This prevents them from pulling stunts that may harm them. Don’t worry if you have already bought a tank without lids. An additional lid can be found in the nearby aquarium store.

    Betta Fish That Needs Larger Tank Size

    Giant Betta Fish
    AI Generated Image: Heaven Gables

    Here are some bettas that need larger tank sizes (more than 5 gallons) -

    Giant Betta Fish

    They need 10 gallons of tank (minimum). They are sometimes referred to as King Betta. This is because they are twice the size of the regular Betta. Hence, they need a room with extra space.

    Betta Sorority

    They are known as sorority bettas because they belong to a school of female fish who love to live in groups. Hence, they need a tank that can hold at least five female bettas, and it must be at least 20 gallons.

    Notes If you’re a beginner, avoid sorority betta. It takes a lot of time and effort to maintain them.

    Conclusion

    It is advisable to pick a tank with a minimum of 5+ gallons to ensure betta fish don’t suffocate. Also, the tank is where they poop, which breaks down into chemicals that make them sick. In smaller spaces, these chemicals build up pretty quickly, leading to severe health issues in bettas. You can also contact your nearby aquarium shop, where they can help you with all the necessary information.

    Table of Content

      Get daily updates to your inbox!

      Subscribe to our mailing list to receives daily updates!

      Related Stories