20 Gallon Betta Tank: Our Top 4 Reviews and Buying Guide

If you are considering upgrading your betta’s home, consider getting a 20-gallon tank.

A larger aquarium gives you more options for aquascaping and provides a more comfortable environment for your betta.

There are several varieties of 20-gallon tank on the market, so how do you know which is best for your betta?

We reviewed several 20-gallon tanks and narrowed it down to four of the best.

So, what is our top choice for the best 20 gallon betta tank?

The Aqueon Fish Tank Starter Kit tops our list because it includes everything you need for your betta tank at a great value.

20 gallon betta tank atf

Our Top 4 Picks for the Best 20-Gallon Betta Tank

  1. Lifeguard Aquatics 20-Gallon Rimless Aquarium (Best Rimless Tank)
  2. Tetra 20-Gallon Fish Tank Kit (Best Overall Tank)
  3. Aqueon Fish Tank Starter Kit (Best Choice for Beginners)
  4. Marina Aquarium Kit (Best Kit for Biological Filtration)

Reviewing the Top 4 Choices for 20-Gallon Betta Tanks

Lifeguard Aquatics 20-Gallon Rimless Aquarium

Lifeguard Aquatics 20-Gallon Rimless Aquarium
  • Ultra Clear low-iron glass
  • Rimless design
  • Foam leveling mat

This tank from Lifeguard Aquatics is our choice for the best rimless tank because of its crystal clear low-iron glass.

German-engineered glue on the seams creates smooth and sturdy joints with polished edges.

This tank includes an insulated foam mat for added protection on the bottom of the aquarium.

The only downside to this tank is the lack of a lid. Bettas can jump out of the tank, so your tank needs a cover.

Lidless tanks also have issues with heat loss and water evaporation.

Mesh netting ensures your betta cannot jump out. But it also takes away some of the aesthetic appeal of this modern tank.

Custom glass lids for rimless aquariums are available online. These lids attach to the top of the tank with a few clips and maintain the sleek look of the tank.

  • Shape: Rectangle
  • Material: Ultra Clear (low-iron) glass
  • Dimensions: 24.4 x 12.2 x 15.74″ inches
  • Special Features: Rimless design, included foam mat

Tetra 20-Gallon Fish Tank Kit

Tetra 20-Gallon Fish Tank Kit
  • Daytime LED lights
  • Self-priming adjustable filter
  • Heater

Tetra’s 20-Gallon Fish Tank Kit is our top choice because it includes almost everything you need for a full tank setup.

The only thing missing from this kit is the substrate and a quality thermometer. You can see our favorite betta substrates here.

A hinged hood with LED lights provides a natural daylight effect for your betta. There are a few complaints about the LED lights not working after six months, likely due to exposure to moisture.

The hang-on-back filter is self-priming and adjustable to a flow rate as low as 10 GPH. There is no issue creating a slow current for your betta.

Some owners say the filter is noisy, but the issue is usually resolved by firmly pushing the intake hose into the unit. This kit includes one bio-filter cartridge.

The 100-watt heater has a built-in thermostat and is preset to a temperature of 78-80° degrees Fahrenheit (25.5-27° C).

A small net, water conditioner, and artificial plants are also included in this kit. Unfortunately, the fake plants are plastic and unsuitable for a betta fish.

Consider purchasing live plants or silk plants for your betta instead.

  • Shape: Rectangle
  • Material: Glass
  • Dimensions: 24.2 x 12.4 x 16.7″ inches
  • Special Features: Filter, heater, and accessories included

Aqueon Fish Tank Starter Kit

Aqueon Fish Tank Starter Kit
  • Low-profile LED hood
  • QuietFlow power filter
  • Submersible heater

Aqueon’s Fish Tank Starter Kit is our best 20-gallon betta tank for beginners. The included heater, filter, and other accessories make setting up a betta tank easy for beginners.

The low-profile hood has integrated LED lights and a cutout for the included hang-on-back filter.

An LED light on the filter lets you know when to change the filter cartridge, providing five filtration stages. While the filter is not adjustable, a sponge baffle can create a more gentle current if the flow is too strong for your betta.

This kit also includes one extra filter cartridge.

A submersible heater with a preset temperature of 78-80° degrees Fahrenheit (25.5-27° C) maintains warm water temperatures.

The included water conditioner sample removes harmful chlorine from tap water.

  • Shape: Rectangle
  • Material: Glass
  • Dimensions: 24.25 x 12.5 x 19.5″ inches
  • Special Features: Low-profile hood, included starter kit

Marina Aquarium Kit

Marina Aquarium Kit
  • Included biological supplement
  • Quiet filter
  • Daylight LEDs

The Marina Aquarium Kit comes equipped with a quiet filter and biological supplement. These add-ons make this our choice for the best 20-gallon betta tank for biological filtration.

A biological supplement adds beneficial bacteria to your betta tank. These bacteria jump-start the nitrogen cycle and convert toxic ammonia and nitrites into less harmful nitrates.

The quiet filter offers easy maintenance with a quick-change cartridge system. It also has a slim design and a sponge strainer at the intake.

One complaint about the filter is the price of the cartridge replacements. This filter requires four cartridges, so replacements can get expensive.

Another issue with the included filter is a rough filter guard. When a betta swims too close to this filter guard, it can tear its fins.

If you have concerns about your betta getting injured, place plants near the filter guard for protection.

Marina’s Aquarium Kit has almost everything except one important component. It does not include a heater, which you need for maintaining warm water temperatures for your betta.

Quality aquarium heaters for 20-gallon tanks are not expensive. Expect an added cost of less than $20 for a submersible heater.

This kit also includes a small net and a water conditioner sample to make tap water safe for your betta.

  • Shape: Rectangle
  • Material: Glass
  • Dimensions: 24 x 12.5 x 16.5″ inches
  • Special Features: Biological supplement, quiet filter, starter kit

Features To Look For in a 20-Gallon Betta Tank

With so many different 20-gallon aquarium options, choosing the best one for your betta is hard.

You must consider a few factors when shopping for a new betta tank.

Getting the right tank for your betta is essential. The aquarium is the foundation of a safe and comfortable environment for your fish.


Aquariums have glass or acrylic walls and floors.

Most 20-gallon tanks are glass, but a few acrylic options are available.

Glass is more durable than acrylic, but it adds to the tank’s weight.

Acrylic is lightweight but is more prone to scratches and warping.

The type of material used also affects the clarity of the tank.

Aquarists appreciate the clear views acrylic provides, but they prefer the durability of a glass tank.

This brings us to a third option: low-iron glass.

Low-iron glass also goes by the brand names Starfire or Ultra Clear, among others.

This type of glass creates a crystal-clear aquarium without the greenish tint of regular glass.

While low-iron glass has the best durability and strength, it is more prone to scratches than regular glass.

If you want the durability of glass with the clarity of acrylic, low-iron glass has what you want. But, prepare to pay a bit more for these benefits.


The construction of your 20-gallon tank also affects its durability.

Some manufacturers use inferior glue or supports, so the tank leaks after you fill it with water.

Always inspect the seams of any tank you have an interest in. High-quality 20-gallon tanks have smooth ground edges and almost invisible seams.

Classic fish tanks have plastic or metal bracing around the top and bottom for extra stability.

Rimless tanks do not have these braces. Instead, rimless tanks rely on high-quality fusing methods and thicker glass for stability.

Many rimless tanks contain low-iron glass, like the rimless aquarium from Lifeguard Aquatics.

Without braces, you have an unobstructed view of what’s inside your tank. This makes rimless tanks more expensive than traditional braced tanks.

The only downside to rimless tanks is they do not have lids. Betta tanks need a cover so this fish does not jump out.

Mesh coverings prevent a betta from jumping out. But they take away from the sleek look of a rimless tank.

Another option is a glass top, which attaches to the tank with special clips.

Choosing a braced or rimless tank is usually a matter of personal preference and budget.


Bettas swim from side to side rather than up and down. These swimming limitations are usually caused by their long, flowy fins.

Wild betta fish live in shallow rice paddies and marshes. These fish are not used to swimming in deep waters.

Your betta also needs access to the surface for breathing fresh air with its labyrinth organ.

The ideal depth for a betta tank is 12″ inches. At this depth, it is easy for a betta to swim to the surface to eat and breathe fresh air.

You must consider the depth of 20-gallon tanks as you shop. Avoid vertical tanks for your betta and choose a horizontal or long tank instead.

Most horizontal 20-gallon tanks are around 16″ inches deep. Close the gap between the bottom and top of the tank with a 3-4″ inch layer of substrate.

Starter Kit or Bare Tank?

22 gallon betta tank starter vs bare

Aquarium starter kits usually come with a filter, heater, and other accessories needed for a tank setup.

These kits are excellent choices for beginners and can save you a bit of money in tank setup costs.

But, inexpensive aquarium kits may not include the best components. The aquarium kits on our list had fewer problems than other 20-gallon kits available.

Research the individual accessories included in aquarium kits to know if they are good quality. Some complaints are due to user error, so be aware of this as you search through reviews.

Bare tanks do not come with any extra accessories. This lets you choose your heater and filter according to your betta’s needs.

A bare 20-gallon tank costs less than a kit. But you must also budget for a quality filter and heater.

Buying individual components may increase your initial tank setup costs. But you save money in the long run by not seeking replacements for faulty filters or heaters.

Are Glass Tanks Better Than Acrylic Tanks?

Glass tanks are usually preferred over acrylic tanks among betta fish owners.

Unlike acrylic, glass does not warp, creating a more stable aquarium.

But acrylic does have some advantages. It is more lightweight and has more clarity than regular glass. An acrylic tank is as durable as a glass tank with proper bracing and construction.

Acrylic tanks are usually less expensive than glass tanks, as well.

One material is not necessarily better than the other. The quality and stability of a tank depends on its construction.

A poorly built glass tank can develop stress cracks due to faulty bracing or improper joins.

Always inspect the seams and edges of any 20-gallon tank before you buy it.

If the tank has visible glue at the seams or appears unstable, it has a higher chance of developing leaks and other issues later on.

What Is the Minimum Tank Size for Betta Fish?

The smallest recommended size for a betta tank is 5 gallons.

Many pet stores sell small bowls meant for bettas, which are bad for the fish.

Tiny bowls do not provide enough space for swimming and are prone to poor water conditions.

A nitrogen cycle cannot become established in a tank smaller than 5 gallons.

Keeping the water clean in small tanks involves a lot of water changes. Frequent water changes create unstable water parameters, which harms your betta.

If you have the space in your home, a 10- or 20-gallon tank is even better for your betta.

Larger tanks let you add more plants and hiding spaces, creating a more comfortable environment for your fish.

A 20-gallon tank also allows you to add some tank mates to your betta tank, but if you’re interested in knowing how many bettas fit in a 5-gallon aquarium, we’ve written on that.

Can Bettas Live in Other Tank Shapes Besides Rectangular?

Rectangle aquariums are the most common shape available.

New shapes like hexagons, cubes, and tall vertical tanks have gained popularity among aquarists looking for something different.

Hexagon and vertical tanks are not good options for bettas because they are too deep.

Cube tanks are not too deep, but they do not provide your betta with a lot of horizontal swimming space.

Long tanks are shorter and longer than traditional rectangular tanks. These types of tanks make a great home for a betta fish.

The only issue with long tanks is they usually do not come with a lid. But, lids are sold separately by a variety of manufacturers.

Check the measurements of your tank to ensure the lid is compatible.

Do You Need a Heater and Filter in a Betta Tank?

heater and filter for betta tank

Despite common beliefs, betta fish need a heater and filter in their tank.

Bettas are tropical fish and need water temperatures ranging from 78-80° degrees Fahrenheit (25.5-27° C). The only way to maintain these warm temperatures is with an aquarium heater.

Low temperatures cause digestive issues and lethargy in bettas. Your betta may become constipated or refuse its food.

For a 20-gallon tank, you need a 60- to 100-watt aquarium heater to achieve the correct temperatures for a betta.

Bettas also need a quality aquarium filter. Filters remove harmful bacteria and circulate the water.

Beneficial bacteria also colonize in filter media.

Without a filter, your betta tank has a higher risk of ammonia spikes and bacteria outbreaks. Your tank would need more frequent water changes, causing unstable water parameters.

An aquarium filter should circulate all the water in your tank 4-6 times per hour. Choose a filter with a flow rating between 80-120 GPH (gallons per hour) for a 20-gallon tank.

Does a Betta Need Plants in a 20-Gallon Tank?

Plants are an essential part of a betta tank.

Live plants filter and oxygenate the water while creating a more natural environment for your betta. Plants also provide hiding spots and visual stimulation for bettas.

Bettas enjoy resting on the broad leaves of some plants. Floating plants offer shade from the aquarium lights and encourage bubble nest building in male bettas.

Silk artificial plants are also a good option, but they do not offer the benefits of live plants. Avoid plastic plants because their sharp edges can tear your betta’s delicate fins.

Some excellent choices for live plants in a 20-gallon betta tank include:

  • Java moss
  • Anubias
  • Java fern
  • Brazilian hornwort

The extra space in a 20-gallon tank lets you create a natural aquascape with several types of plants.

Is a 20-Gallon Tank Large Enough for a Betta Community Tank?

A 20-gallon betta tank has enough space for a few tank mates.

Do not attempt a community tank in anything smaller than 10 gallons. Bettas need their own territory and become aggressive when other fish enter their space.

Certain species of small schooling fish, bottom dwellers, make great tank mates for bettas.

Keeping small groups of fish lowers the risk of a single fish getting bullied by your betta.

Avoid colorful fish and known fin nippers to lower the risk of aggressive behavior in your tank.

Use caution when housing your betta with shrimp. Your betta may see the shrimp as a meal, even if the shrimp is large.

I know of at least one owner whose betta choked on a large shrimp because it could not resist the temptation.

Keeping your betta well-fed usually prevents these types of incidents.

Never put two male bettas in the same tank, no matter how large it is. Male bettas are aggressive and may fight to the death over territory.

Female betta fish can live in sororities, but you need at least a 30-gallon tank for success.

How Much Substrate Does a 20-Gallon Betta Tank Need?

betta tank substrate

Gravel is the most common substrate used in betta tanks.

Fish keepers prefer gravel over sand because it creates less mess and anchors aquarium plants.

One pound per gallon of water is a general rule of thumb for how much gravel you need. This amounts to around 3-4″ inches of gravel.

Choose small, smooth gravel to prevent fin injuries.

Gravel substrates come in many different colors, from neon to neutral. Neon colors brighten up your tank, and neutral colors create a more natural habitat.

Light colors of gravel enhance the look of darkly-colored bettas. On the same token, dark-colored gravel makes a bright betta stand out.

A Closer Look at Our Favorite Options for 20-Gallon Betta Tanks

The Tetra 20-Gallon Tank Kit tops our list because it includes everything you need for a successful betta tank setup. A quality filter and heater ensure you won’t have a lot of issues getting your tank up and running.

If you want a modern look, the Lifeguard Aquatics 20-Gallon Rimless Tank is a good choice. The low-iron glass gives you a clear view of your betta.

Keep in mind you will need to buy a separate lid for your rimless tank.

The Marina Aquarium Kit gets our vote for the best kit for biological filtration.

With an included biological supplement and four-cartridge filter, beneficial bacteria can get a head-start in your betta tank.

Frequently Asked Questions About 20-Gallon Betta Tanks

Can bettas be in a 20-gallon tank?

Bettas can thrive in a 20-gallon tank.

A 20-gallon tank gives your betta more room for swimming and exploring.
The larger tank provides more space for plants and decorations and allows you to create the best environment for your betta.

You also have the option of adding tank mates for your betta in a 20-gallon tank.

What fish can live with bettas in a 20-gallon tank?

Bettas can get along well with peaceful fish and invertebrates in a 20-gallon tank.

Suitable betta fish tank mates include:

– Neon tetras
– Harlequin rasboras
– Otocinclus catfish
– Corydoras
– Mystery snails
– Amano shrimp

Always quarantine new fish before placing them in the same tank as your betta. Fish can carry contagious diseases and cause your entire tank to become ill.

If you see any signs of aggression in your community tank, you must separate your fish. This prevents further aggression and injury.

Bettas have a history of aggressive behavior, but a docile betta can get bullied as well.

Can a betta fish tank be too big?

There is no fish tank too large for a betta fish.

A larger tank works well if the tank is shallow and you provide plenty of plants where your betta can rest.

Your betta will enjoy having a large tank to explore. Since bettas are a solitary species, you don’t have to add tank mates if you don’t want to.

Do bettas prefer tall or wide tanks?

Bettas are not strong swimmers because of their long, flowing fins.

They have a difficult time swimming to the surface from deep waters. Your betta fish needs access to the surface for eating and breathing fresh air.

A tall tank is not suitable for a betta fish. A horizontal or long tank is much better for a betta.

What do bettas like in their tank?

Providing stimulating items in your betta’s tank prevents boredom and depression.

Bettas love swimming among live plants and resting on the leaves. Floating plants and betta hammocks are popular choices for betta fish.

Hiding places make bettas feel more secure.

Items like coconut caves, pieces of driftwood, and smooth rocks give your betta more places for hiding and exploring.

Your betta may also like Indian almond leaves. These leaves tint the water and create a blackwater environment.

Blackwater conditions mimic a betta’s natural habitat, making your fish feel more comfortable and secure.

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Toni Tedescucci is a freelance writer who loves all animals, especially betta fish. When she isn’t busy writing for Betta Fish Bay, she’s spending time with her family or getting cozy with her cats and a good book.

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