3.5-Gallon Fish Tank: Our Top 3 Choices on a Budget

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They say bigger is better. But honestly, nothing beats a small, self-contained aquarium system.

Smaller aquariums are indeed more difficult to keep than larger ones, but the challenge can make the results that much more rewarding.

Successfully running a 3.5-gallon (13.2L) is no easy feat, but these pico systems can surprisingly hold an abundance of life.

Keep reading to learn everything you need to know about setting up and maintaining a pico tank and the best 3.5-gallon aquariums available for your freshwater or saltwater needs!

Benefits of a Small Tank

There are a few benefits to having a smaller size tank, even though it can be more challenging than a larger one. 

Here are some of the benefits of having a pico aquarium:


Of course, a smaller tank will take up less space than a larger tank. This is especially important for hobbyists that might not have a lot of room to allot to a tank but still want to bring a piece of nature into their homes.

These aquariums often do not need a special aquarium stand and can be safely placed on common household furniture.


An aquarium can be expensive to set up and expensive to run. Larger tanks can pull a lot of energy, meaning that electrical costs will be increased.

A smaller tank means that the equipment needed to run the aquarium will be less powerful, meaning less expensive. As these aquariums use less energy, bills will also be much cheaper.


There is something very aesthetically pleasing about having a small container of water with life inside of it.

This, in addition to the freedom of placement, definitely brings a unique feature to a living space that larger tanks otherwise overwhelm.


Though small tanks can be difficult to maintain, the actual amount of maintenance needed to run them successfully at any given time is much less than that of a larger system. 

As long as maintenance is regular and consistent, it should only take a few minutes every few days or so. 

Challenges of a Small Tank

Many long-term hobbyists think small tanks are much more challenging than large tanks. This is somewhat true as large tanks are much more forgiving of instability and allow for greater diversity overall.

Though small tanks usually aren’t as difficult as they’re made to appear, some challenges come along with having them:

Finding Equipment

Even though the equipment is cheaper for smaller tanks, nano and pico equipment can be difficult to find; it can also take some trial and error to choose correctly sized and powered equipment.

Because of this, most equipment will need to be ordered online.


Stability is probably the biggest challenge of keeping a smaller tank. Less water volume means less room for error.

As we’ll discuss, maintaining a small community tank usually means performing 100% water changes, which can cause a lot to go wrong.

Limited Livestock

You have to go into a small tank knowing that there aren’t many fish, plants, or invertebrates to choose from. That being said, there are still some exciting options for a 3.5-gallon tank.  

3.5-Gallon Fish Tank Setups

What are some ways you can set up your 3.5-gallon tank, anyway?

Believe it or not, you can create some pretty intricate freshwater or saltwater ecosystems in these small tanks. 

Hobbyists have had success with everything from fully planted tanks to marine reefs with challenging corals, like small polyp stony (SPS) species. The possibilities will only be limited by how much time and effort you’re willing to put in.

Though not necessary, it is recommended to have some experience with fishkeeping larger systems before attempting something in this niche.

How Many Fish Can You Keep in a 3.5-Gallon Tank?

Not many tropical fish can comfortably fit into a 3.5-gallon tank, but most hobbyists choosing this size aren’t looking to keep fish.

Instead, there are various shrimp, plant, snail, and coral species that would quickly fill up the tank. 

For freshwater tanks, 3.5-gallons can house many colorful shrimp, such as cherry shrimp (Neocaridina davidi).

For saltwater tanks, there are also some mini shrimp and corals available.

Can Betta Fish Live in a 3.5-Gallon Tank?

This is a very heated subject in the aquarium-keeping hobby. Exactly how many gallons a betta fish needs to thrive has been up for debate for years.

Most hobbyists agree that 5-gallons (18.9 L) is the absolute minimum. Others think that slightly smaller is okay as long as parameters are maintained.

We think that 3.5-gallons is enough for a single betta fish as long as it is naturally planted and water changes are kept up with.

Of course, always try to get your fish as big of a tank as possible. If you’re an expert betta fish keeper though, then a tank this small should be enough.

Maintaining a 3.5-Gallon Fish Tank

That being said, how do you make sure that your 3.5-gallon aquarium stays running? Smaller tanks are notorious for being more difficult because water parameters can easily swing.

The best way to keep your community tank healthy is by performing 10-25% weekly water changes; some hobbyists choose to do near 100% changes, though this should only be attempted if the water parameters of the new tank water match exactly.

Take care to disturb the substrate as little as possible. Rinse the filter media when needed. Make sure to remove all uneaten food shortly after feeding time ends.

The Best 3.5-Gallon Fish Tanks

Finding a small tank can be difficult. Most hobbyists choose to go for traditional fish tank sizes and the little ones get forgotten.

Some pico tank keepers get creative with their setups and use various glassware that they come across.

Here are some of the best 3.5-gallon tanks for aquarium use based on customer reviews, price, appearance, and usability!

Koller Products AquaView 3.5-Gallon Fish Tank with Power Filter & LED Lighting

Koller Products AquaView 3.5-Gallon Aquarium

  • FUN and REWARDING: Are you looking to buy an aquarium for your family? If you are, you are going to want to look at this fish tank.
  • DAZZLING COLORS: Energy-efficient LED lighting with 7 dazzling color selections to brightly illuminate your fish, choose daylight white, blue, green, amber, aqua, purple, or red.
  • COMPLETE FILTRATION: Powerful internal power filter cleans and purifies aquarium water at a flow rate of 25 gallons per hour effectively removing organic pollutants including discoloration, odors, heavy metals, and toxic gases.

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The Koller AquaView 3.5-Gallon Fish Tank is a simple yet somewhat efficient design. This tank set up is especially geared towards beginner hobbyists who might be on a tight budget.

This plastic aquarium kit includes a battery-operated LED light that features seven different colors, a 25 GPH internal filter, and a secure lid. Though this AquaView aquarium is inexpensive and seemingly all-inclusive, there are some major problems with it. 

For one, the LED lights run out of battery very quickly and are not very vibrant. The filter is a good slow flow rate for betta fish, but breaks down very quickly and needs to be cleaned regularly.

There is also a design flaw with how the filter fits with the lid, and the tank cannot be filled to the top with water.

That being said, this aquarium does have a purpose. It can comfortably house a betta fish and offers 360-viewing if the lighting is replaced.

What We like:

  • Simple setup with included light and filter
  • 360-viewing design
  • Lightweight and compact

Room for Improvement:

  • Battery-run dim light
  • Malfunctioning filter
  • Plastic

Top Fin® Enchant Aquarium – 3.5-Gallon

The Top Fin Enchant Aquarium is a similar design to the Koller 3.5-gallon but comes with a more dependable aquarium name.

This plastic aquarium setup includes a Top Fin “Element” filter, two replaceable filter cartridges, a color-changing light, and a secure lid. Unlike Koller Products, Top Fin’s light comes with a controller and electrical cord for a much brighter output.

Sadly, there are still some problems with this fish tank. The major problem that hobbyists run into is with the tank filter.

For the first few days after installation, the filter works perfectly. However, it starts to become very loud with a grinding noise. Eventually, it will stop working entirely.

On top of the faulty filter, the plastic of the tank is not very durable and is easily scratched and cracked. 

What We like:

  • Recognized aquarium brand
  • Included filter, filter cartridge, and LED light (wired)
  • Half-circle design for multiple viewing angles

Room for Improvement:

  • Filter quickly malfunctions
  • LED lighting could be brighter
  • Plastic easily scratches and cracks

Imagitarium 3.7-Gallon PRO Deluxe Freshwater Aquarium

Imagitarium 3.7 Gallon PRO Deluxe Aquarium

  • 3.7 Gallon Desktop Fish Tank from Imagitarium
  • White and blue 3 watt LED light strip and power button
  • Glass Lid
  • Filter sponge, carbon filter cartridge and zeolite filter cartridge included

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For about double the price, you can get a quality and versatile pico aquarium. A little bigger than the others, the Imagitarium 3.7-Gallon PRO Deluxe Freshwater Aquarium can be used for both freshwater and saltwater purposes. 

This glass aquarium comes with white and blue 3 watts LED lighting, a glass lid, and supplies for internal filtration including the filter sponge, carbon media, submersible pump, and nozzle.

It is important to keep in mind that the internal filtration will take away from the swimming space in the front of the tank, further limiting stocking options. 

The biggest issue with these aquariums is that the filter supplies can be difficult to find. Though less likely to fail than the other two fish tanks, this Imagitarium setup requires specific filter media and parts that can be hard to replace.

Hobbyists have also found that the silicone wears down over time.

What We like:

  • Glass aquarium with included LED lighting
  • LED lighting strong enough to support some live plants
  • Internal filtration for clean look and customizability

Room for Improvement:

  • Filter media and parts difficult to find
  • Silicone sometimes cracks
  • Internal filtration takes away tank space


If you’re just diving into the world of pico tanks, then be prepared for a challenge. While these tanks are more difficult to keep than larger ones, many hobbyists have successfully kept thriving reefs and densely planted mini-ecosystems for years

As with any part of the aquarium-keeping hobby, a good community tank will always start with having good basics, including the fish tank itself!

If you have any questions about pico tanks, fish, or shrimp species that are suitable for smaller setups, or if you have had experience setting up a tank that’s even smaller than 3.5-gallons, don’t hesitate to leave a comment below!

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