20-Gallon Betta Fish Tank
You can’t escape the tank debate if you’re in the fish hobby. Betta fish and tank size go hand in hand. The options of tank sizes range from tiny bowls and smaller tanks of 0.5 and 1 gallon to 100+ gallons. We have specialized the ongoing article for a 20-gallon betta tank so that if a betta enthusiast intends to buy it, he has clear guidelines regarding its setup and all essential considerations.
Is a 20-Gallon Tank Too Big for a Betta?
Most betta owners hesitate to get or upgrade their tank to a bigger size, like 20 gallons. They think that such tanks are too big to handle or maintain. Another misconception is that these tanks are exclusively used for breeding purposes. However, the fact is the opposite.
Larger tanks are beneficial and easy to maintain compared to smaller ones. They’re also closer to the ideal size for betta fish. If your space and budget limitations allow you to buy a 20-gallon tank, confidently go with it.
Why Should You Buy a 20-Gallon Tank for Your Betta?
A 20-gallon tank is a perfect choice for your betta fish. It offers numerous benefits for their health, behavior, and overall well-being. It reduces the burden of too much effort in terms of tank maintenance. A 20-gallon betta tank provides ample space for your betta and all the inhabitants of the tank, including betta fish mates, plants, and decorations.
If you are interested in aquascaping, it allows you to create the ecosystem of your dreams. Such tanks are not only a favorite of your betta fish but also add extreme delight and beauty to your room.
Advantages of 20-Gallon Betta Tank
A 20-gallon tank offers more swimming room and space for plants and decorations for betta tank mates. It provides the opportunity for better mental stimulation and exercise for your betta. It has been the experience of many betta owners that their bettas feel happier and more active in a spacious environment.
A 20-gallon tank effectively dilutes water toxins such as ammonia and nitrite in more water, reducing their buildup. It will also keep you in your comfort zone by demanding less maintenance efforts, such as water changes and cleaning the tank.
The tank has plenty of space for live plants, and they don’t need frequent trimming due to the extra space. Adding live plants helps filter the water and absorb harmful toxins. In a well-maintained 20-gallon tank, we perform a 25% water change every 5-6 weeks, and the betta thrives happily there.
A 20-gallon tank allows you to be more creative in ensuring hiding spots and arranging decorations that turn the tank into paradise.
Ideal Tank Dimensions
Tank dimension is an unignorable factor when considering tank size, especially when you opt for a bigger tank. Longer tanks are preferable over taller tanks, as the former provides more surface area and swimming space. They also contribute to less hydrostatic pressure on the delicate betta fish.
Long vs Tall Tanks
The longer and shallower tanks align with the betta fish’s natural habitats, which are shallow ponds and rice paddies. Shallow tanks make it easy for labyrinth species like betta to access the tank surface to breathe air.
If you have been gifted with a taller tank or bought one unknowingly, you will need to make certain adjustments to overcome the challenges of taller tanks.
Short-finned betta species like plakats or giant bettas face fewer challengers in taller tanks than long-finned bettas. It’s not so that bettas can’t survive in taller tanks at all. They do, however, require certain precautionary adjustments.
Place broad-leave plants like Anubias, Java ferns, or betta hammocks to create resting spots at various levels so bettas can easily access the surface. Opt for those plants that grow taller than broader so that you don’t need frequent trimming. If the plants don’t reach the upper portion, anchor plants to the tank sides or use fake plants. It may help grow plants in the upper areas of the tank.
Best Tank Mates for a Betta in a 20-Gallon Tank
Large tank and betta mates – this is why most betta enthusiasts opt for a 20-gallon tank. Some betta owners want a livelier environment in their tanks, which is only ensured if you have betta mates in such a large tank. Though we have covered this topic separately, we highlight it here for your convenience.
Test Betta Compatibility
Test your betta’s temperament before putting tank mates in its tank. Do the same for the chosen tank mate. If the two are aggressive, step back from letting the two be mates. Male betta can’t go with other males or any aggressive fish that looks similar
Keep those bottom creatures that share the requirements with bettas. Start with hardy snails or shrimp to observe betta’s behavior. Keep a backup 5-gallon tank ready in case the betta shows aggression.
An Infographics for Betta Tank Mates
Live Plants for a 20-Gallon Betta Tank
Adding live plants to a betta tank is essential. A heavily planted tank mimics a natural habitat and oxygenates it. An unenriched tank from the inside can stress your betta or tank mates.
Whatever plants you choose for your tank, ensure the following conditions to promote plant growth.
- Low to moderate-lighting plants, as the high-light-demanding plants, can promote algae growth.
- Nutrient-rich substrate to help the rooted plants thrive.
- Low-maintenance plants that don’t require CO2 injection.
A Summarized Table for Live Plants in 20-Gallon Betta Tank
| Plant Name | Why It’s Great | Placement | Care Level | Notes |
| Anubias | Hardy, slow-growing | Mid-ground or attached to rocks | Easy | Not bury rhizome to prevent rot. |
| Java Fern | Hardy and ideal for betta tanks. | Mid-ground | Easy | Grows well in low-light tanks. |
| Java Moss | Versatile and provides hiding spaces | Foreground or on decorations | Easy | Great for creating carpets |
| Amazon Sword | Large and lush, adds a natural aesthetic. | Background | Moderate | Requires nutrient-rich substrate; may grow large. |
| Cryptocoryne | Compact and ideal for mid-ground placement. | Foreground/Mid-ground | Moderate | May experience “crypt melt” when introduced. |
| Marimo Moss Balls | Unique and low-maintenance algae spheres. | Foreground or floating | Easy | Helps reduce nitrates and algae. |
| Water Wisteria | Fast-growing and helps maintain water quality. | Background or floating | Easy | Can be planted or left floating. |
| Hornwort | Fast-growing and provides shade. | Floating or background | Easy | Does not require substrate. |
| Vallisneria | Creates a grassy look and natural cover. | Background | Easy | Thrives in a wide range of conditions. |
| Duckweed | Floating plant that reduces light intensity. | Surface | Easy | Ensure it doesn’t block too much light. |
| Salvinia | Floating plant with small, attractive leaves. | Surface | Easy | Great for bettas who enjoy surface cover. |
Our Recommended 20 Gallon Betta Fish Tanks
GloFish 20 Gallon Aquarium Kit
(View it here on Amazon)
| Pros | Cons |
| Tank is well-built with no leaks or major defects. | Filter is underpowered for a 20-gallon tank. |
| Comes with two lighting options: blue “Glow Fish” lights and white lights. | Filter suction line is too short, requiring an additional extension to reach lower areas. |
| Heater maintains water at around 78°F (indoor temp at 70°F). | Heater is non-adjustable and insufficient for colder environments. |
| Includes starter accessories like fake plants and gravel. | Lid is made of thin, flimsy plastic that cracks easily during setup or use. |
| Attractive tank design with good LED lighting for display. | Black gravel with colored acrylic pebbles is messy and difficult to wash. |
Tetra Color Fusion Aquarium 20 Gallon Fish Tank Kit
(View it here on Amazon)
| Pros | Cons |
| Beautiful tank with color-changing lights | Filter is noisy, unreliable, and overly complicated |
| Easy to set up with included accessories | Tank lid is flimsy and prone to breaking |
| Comes with starter decorations | Included filter and accessories are not long-lasting |
| Tank matches its description and arrives in good condition. | Lacks additional tools, like a cleaner for debris |
| Ideal for beginners or kids with basic requirements. | Lighting is not very strong, making it less suitable for live plant setups. |
Setup of 20-Gallon Betta Tank
As a beginner, you might be perplexed by the long 20-gallon betta tank setup. However, the bigger the tank, the easier it is to set up.
To set up a 20-gallon betta fish tank:
- Start by cleaning the tank, substrate, and decorations with warm water.
- Add 1–2 inches of substrate and arrange decorations for hiding spots and swimming areas.
- Fill the tank with de-chlorinated water.
- Install a gentle filter, heater (set to 78–82°F), thermometer, and appropriate lighting.
If you are unsure about these items, such as which one to buy, you can explore our comprehensive articles betta fish filter, lighting, and heater.
- Now, allow the tank to cycle for 2–4 weeks to establish beneficial bacteria.
- Pass the water from testing its parameters to ensure ammonia and nitrite are at 0 ppm.
- Add live plants (mentioned above) for enrichment and improved water quality.
- Once cycled, acclimate the betta by floating its container in the tank and gradually mixing water before releasing it.
The rest is taking care of your tank, for which you can visit our article about betta fish care.
Feeding in Community Tank
Feeding in community tanks requires careful planning to ensure all species get adequate nutrition without leading to fight and competition. To do it effectively,
- Identify the specific dietary needs of each species in your tank.
- If unsure about proper food, choose a combination of pellets, frozen, or live foods.
- Use sinking pellets or wafers for bottom dwellers like kuhli loaches or corydoras.
- Follow a proper feeding schedule.
- Remove the uneaten, leftover food in the tank using a siphon or net.
- If your betta eats food meant for other tank mates, separate the betta in the breeder box during feeding.
Transition Challenges
Older Bettas transitioning from smaller tanks to larger ones may experience temporary stress or depression due to the unfamiliar environment. Acclimate the betta when adding it to a new tank. Add a small amount of clean water from the old tank to the new one to make it familiar. Similarly, provide consistent hiding spots and plants to help them adjust.
