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Best small fish tank: Five gallon and under fish tanks to suit every budget

best small fish tank
(Image credit: Koller Products)

Choosing the best small fish tank for your finned friends is no mean feat when there's plenty of choice on the market. Whether you're looking to add a touch of class to the home, reduce work stress or simply love the idea of watching them explore their new home, fish make for delightful pets that enthrall and relax those around them.

If you're new to choosing the right pet fish for you, you'll likely be thinking not just about your new pet's residence but also any additional fish tank accessories that will go inside or out. As as well as the tank itself, you may also be considering a fish tank stand to provide additional support or style.

Then, there's the essentials for fish care. A fish feeder ensures your pets gets the right amount of each day, while selecting the right fish food is key.

In contrast to the 20-gallon-plus behemoths that are out there, small fish tanks are designed to be compact and beautiful but they don't offer the excitement of building up a large aquatic landscape for your pets. If you're not sure what size will be right for your fish, our overall guide to the best fish tank can set you on the right path. 

Otherwise, the requirements for a small fish tank remain the same as for larger tanks. You will need to heat and filter them, populate them with just enough fish, never too many, and of course, feed those fish. Then there’s a small amount of maintenance, such as cleaning, changing water and filter cartridges. 

Fulfil these simple requirements, and a small fish tank can repay its setup costs many times over in terms of satisfaction and enjoyment. 

PetsRadar's pick of the best small fish tanks

  • Best overall small fish tank: MarineLand 5 Gallon Portrait Glass LED Aquarium Kit
  • Best budget small fish tank: Tetra Crescent Acrylic Aquarium Kit 5
  • Best small fish tank for Bettas: Aqueon LED MiniBow Aquarium Starter Kit
  • Best small fish tank for colored lighting: Koller Products AquaView 4.5-Gallon
  • Best small fish tank for low-light environments: GloFish Aquarium Kit w/ Hood, LED Lights and Whisper Filter

best small fish tank

(Image credit: Company name)

MarineLand 5 Gallon Portrait Glass LED Aquarium Kit

Best overall small fish tank

Volume: 5gal | Heater capacity: 50W | Weight: 12lbs | Dimensions: 11.8” x 11.6” x 17”

Looks great
Complete kit
Hidden filtration
More expensive than many

Sleek and elegant, MarineLand’s upright tank looks great wherever you put it. Five gallons isn’t a lot of water, but it’s enough for a thriving community of colorful fish as long as you stay on top of filtration and maintenance.

MarineLand’s tank contains a three-stage filter that uses replaceable activated carbon cartridges – you’ll go through one every month or so – and also comes with a Tetra submersible heater that’s pre-set to a suitable temperature. 

The pack of three artificial plants that comes in the kit is enough to be starting off with, but you may find you want more to provide a complete-looking display. The back of the tank is black, so a wall of greenery that will push fish forward where you can see them best will look good. Thanks to the height of the tank, it’s possible to use taller aquarium plants, which can look especially attractive.

The tank sits on a sturdy plastic base, held in place by its own weight, and the front and sides are made from one piece of seamless glass. Lighting comes from blue and white LEDs, giving a natural shimmering look to the water as it circulates as well as a moonlit appearance if switched on at night. 

One reason we like this tank so much is the ease with which the equipment can be accessed – a glass canopy slides toward the rear of the aquarium, opening it up for both feeding and maintenance. The only downside to this is that the filter compartment takes away 2” from an already small tank, and if you're using live plants then debris from these can collect around the filter, becoming hard to remove.

best small fish tank

(Image credit: Tetra)

Tetra Crescent Acrylic Aquarium Kit 5

Best budget small fish tank

Volume: 5gal | Heater capacity: N/A | Weight: 1lbs | Dimensions: 16” x 11.2” x 13.2”

Market-leading brand
Curved front
No heater

With its curved front and bright LED lights, Tetra’s Crescent will stand out wherever you place it. Moulded from one piece of acrylic, with a separate lid and base, the curving front enhances the visibility of your fish.

Inside, you get the popular Tetra Whisper power filter, but no heater is included. This is fine if you’re only going to keep room-temperature fish, but anyone who dreams of bright, tropical specimens will need to add a heater to bring the temperature up to around 77F. 

The slim black cover contains the LED lights that are bright enough to encourage live plants to grow, but plastic plants will be equally at home. Their intensity sets off the colors of fish nicely too. There’s also an uncovered oval in the cover for feeding – cautious owners might want to cover this with a mesh panel to avoid jumping fish accidentally using it as an exit.

Filtration media comes in the form of disposable Bio-bags, which can be switched out easily enough from the black, cylindrical filter. They have a dual-sided mesh to catch floating debris, a layer of carbon to remove odors and discoloration, and incorporate Tetra’s Water Clarifier to prevent the buildup of particles in the water and on the glass. The Whisper filter is a popular choice, and if properly maintained will do its job with the minimum of noise.

best small fish tank

(Image credit: Aqueon)

Aqueon LED MiniBow Aquarium Starter Kit

Best small fish tank for Bettas

Volume: 5gal | Heater capacity: N/A | Weight: 1lbs | Dimensions: 15” x 10.7” x 15.4”

Elevated base
Curved front
Power filter
No heater
Easily scratched

Betta fish are a popular choice for emergent fishkeepers, and due to their ability to breathe from the surface using an organ known as the labyrinth. The best-known of the genus is the beautiful Siamese fighting fish – only to be kept on its own or with carefully chosen tank mates – but there are many other bettas that don’t display the same level of ferocity. 

The popular perception of bettas is that, because of their breathing habits, they can be kept in a small enclosure, but they thrive in five-gallon tanks such as this one. It’s worth noting that Bettas, as with many fish, require a water temperature of 76-81F, so if your room is cooler, look into a tank with a heater, or add one to this kit.

The tank itself is acrylic, but in contrast to the scratch-resistant materials available elsewhere this one is easily scratched. This isn’t an issue once the tank is set up, but can be during delivery. The tank ships in its own container for protection against scratches, but accidents happen. The curved front looks great once it is filled and lit, and the Aqueon power filter provided takes up little space. 

best small fish tank

(Image credit: Koller)

Koller Products AquaView 4.5-Gallon

Best for colored lighting

Volume: 4.5gal | Heater capacity: N/A | Weight: 1lbs | Dimensions: 14.6” x 10.75” x 13.25”

Impact-resistant acrylic
Seven LED colors
Looks great
No heater

Looking incredible on a shelf or desk, this Koller tank offers seven different colors of LED light and four transitions to show off your fish and really attract attention. 

The design of this tank is so simple as to be an immediate winner – a simple rounded rectangle of acrylic, with no seams or sharp corners whatsoever. You can see the fish from any angle, as the power filter only takes up a small amount of space at the top of the tank’s rear.

This filter takes simple dual-sided cartridges that wrap activated carbon in a poly-fiber floss that strains out floating particles while the carbon takes care of water discoloration and odors. It’s worth noting that the filter is quite powerful, so anyone intending to keep long-fined or weak-swimming species might like to place a piece of mesh over the inlet to prevent fish being sucked inside.

That single-piece construction means the tank is more-or-less leakproof, and with the bright LEDs shining down makes the tank perfect for places where it might get a little knock now and then. As with all tanks, it’s not going to put up with repeated pummelling, but anyone considering a tank for a child’s room would do well to add this one to their list. 

The lights can be changed to seven colors: amber, aqua, blue, green, purple, red, and white. They can be locked to a single shade, or set to cycle. 

best small fish tank

(Image credit: GloFish)

GloFish Aquarium Kit w/ Hood, LED Lights and Whisper Filter

Best small fish tank for low-light environments

Volume: 3gal | Heater capacity: N/A | Weight: 2lbs | Dimensions: 14.6” x 8.8” x 11.2”

Bright colors
Good filter
No heater
Not to everyone's taste

GloFish products may not be to everyone’s taste, designed as they are to display the almost garish colors of the company’s own line of extra-bright fish (bred with a fluorescence gene, they glow under the right lighting conditions). To this end, you get LED lights that emit the exact shade of blue necessary to set off a colorful display in the right fish, but which may not suit those sourced from elsewhere.

The kit itself is a nice one, however. The tank is a seamless acrylic design with a curved front that should show off its inhabitants to their best. The Tetra Whisper filter included is a popular model that will keep the water clear and is easy to service, dropping a new cartridge in every month or so and disposing of the old one. 

GloFish makes plenty of products to accessorize your aquarium too, with plastic plants that will glow under its lights, ornaments, and even colored gravel to add some interest to the bottom of the tank. The lights themselves are neatly hidden in a slim black hood that should help reduce evaporation and protect from the heartbreaking danger of fish jumping to their doom.

Ideal for low-light environments or even as a night-light in a bedroom, the GloFish tanks are a unique experience. 

How to choose the best small fish tank

Once full of water, even the smallest fish tank can be surprisingly heavy, so make sure you are sitting it in a position that will be able to take the weight long-term. Tanks smaller than four or five gallons aren’t really worth considering, as they will not be able to give your fish the space and turnover of water they will need to live a happy life. 

Modern curved-front tanks look great, those that are curved all the way around look even better, and the acrylic that makes these curves possible also means that they’re lighter when not filled.

It’s important not to over-stock your tanks, even if the water is churned up by a powerful filter, so try to stick to the old rule about having one inch of fish to one gallon of water, excluding tails. So in a five gallon tank, you can have five inch-long fish. Modern filtration may allow you to push this rule to its limit, but the more fish you have, the more important it is that you carry out regular maintenance to keep the water in top condition. Most cartridge-based filters expect you to change the cartridge every month, but this may drop to every two weeks if you’ve got a lot of messy fish.