The 9 Best Small Fish Tanks of 2026

Best Overall

Fluval Flex Aquarium Kit

$117 at Amazon $117 at Chewy $150 at Petco

The Fluval Flex is the best small tank on the market because it comes with all integrated features, including lighting and filtration, and is one of the larger “small” tanks, providing a 9-gallon capacity. When it comes to fish-keeping, more water is always better.

The Fluval Flex has a curved front, but since it is glass, cleaning is easy, provided you move your algae scraper up and down rather than side to side. The lights are completely customizable and include special effects such as cloud cover and storm, making it an appropriate choice for tropical freshwater and saltwater species.

The best part about the Fluval Flex is its integrated filtration. It has a very large sponge (which takes up a fair amount of space) that tucks into the back of the aquarium with pockets for both zeolite and carbon, which you can use if you want or remove.

These sponges will last you for years and never need to be replaced. They are easily accessed, and there is even room for an aquarium heater in the back filter area, allowing your fish more room to swim.

Overall, the Fluval Flex is the best choice you can make for a small aquarium. It is well-suited to many species and will maintain an excellent environment for happy and healthy fish for years. And if you want to go a little bigger, there's a 15-gallon Fluval Flex kit too.

_{Dimensions: 13 x 14 x 13 inches | Gallon Capacity: 9 | Material: Plastic case with glass sides | Accessories: Integrated lights, filter media (sponge, zeolite, carbon) | Inhabitants: Betta, small school, shrimp}

Best Nano

Fluval Spec Aquarium Kit

$125 at Amazon $125 at Chewy $189 at Wayfair

If you don’t have a lot of space but want a great home for your betta or other small fish, the Fluval Spec 5-gallon tank is a fantastic choice. It features a long, rectangular design, which is great at allowing filter flow to be dissipated over a longer distance, rather than crashing into the side of your tank and causing a rough current. It also comes with an integrated filter with a sturdy sponge, zeolite ceramics, and carbon, which can be changed as desired.

This newer design also has an improved light, which has been designed specifically for live plants. Since this is such a small system, your aquatic plants may not be able to subsist on fish waste alone, so you may need to look into some fish-safe plant fertilizer.

_{Dimensions: 21 x 8 x 12 inches | Gallon Capacity: 5 | Material: Plastic case with glass sides | Accessories: Integrated lights, filter media (sponge, zeolite, carbon) | Inhabitants: Betta, small school, shrimp}

Best for Bettas

Fluval Betta Premium Aquarium Kit

$100

$75 at Amazon $100 at Petco View on Walmart

Any nano tank needs to be very well planned, since a lot can go wrong in a small space. But if you are looking for a home for your betta or another small group of fish and do not have much room, you can’t go wrong with the Fluval Betta Premium Aquarium Kit. This tank has been specifically designed with bettas in mind and has many adaptations to make your betta feel right at home.

Like its bigger cousin, the Fluval Spec 5-gallon tank, this aquarium is fully integrated with a durable filter and lighting, but there are a few key features that are betta-specific. This tank has a diffuser for the return, creating less of a water current for delicate bettas to have to swim against.

It also has an integrated heater, which isn’t the best model, but when you are only heating 2.6 gallons, this can be a hard job for any heater to accomplish consistently. We highly recommend getting a thermometer to ensure proper function. And like many of these tanks, it comes with a lid, which is very important for jumpy bettas!

_{Dimensions: 11 x 9 x 15 inches | Gallon Capacity: 2.6 | Material: Plastic case with glass sides | Accessories: Lights, filter media (sponge, zeolite, carbon), heater | Inhabitants: Betta, shrimp}

Best Kit for Beginners

Marina 5 Gallon LED Aquarium Kit

$68 at Amazon $87 at Chewy

The Marina LED Aquarium Kit is an all-in-one kit that's perfect for first-time aquarium owners. It includes a 5-gallon tank, a filter with cartridges that are easy to change, a water conditioner, an integrated hood LED light, a bacterial starter, a soft net, a start-up guide, and even a few fish food flakes. This is a reliable kit to get started with a small selection of fish, like bleeding heart tetras, goldfish, guppies, or betta (the kit even has pictures of these fish on the box).

With this kit, you will need to add a few cleaning tools, such as a glass cleaner and a gravel siphon, and a heater, if your fish needs one. Everything included in the kit is useful and high-quality, though we strongly recommend getting an in-tank thermometer so you know the water temperature in the aquarium is ideal for your fish. We also suggest bypassing the provided fish food flakes and instead getting fish or shrimp pellets to feed your aquatic inhabitants.

_{Dimensions: 16 x 8.5 x 10.5 inches | Gallon Capacity: 5 | Material: Plastic case with glass sides | Accessories: Filter, light, bacteria starter, water conditioner, net, fish food, starter guide | Inhabitants: Betta, small school, goldfish}

Best Upgrade Kit

Coralife LED BioCube Aquarium Fish Tank Kit 16 Gallon

$350

$320 at Amazon View on Petco

When you're ready for a larger tank to accommodate more fish, the Coralife Aquarium Fish Tank Kit is an ideal solution. At 16 gallons, this tank allows you to add bigger schools of fish, from guppies to neon tetras and white clouds. Plus, with the integrated filtration chamber that is built right into the back of the aquarium and the quiet submersible pump, this tank is not only easy to set up but also easy to maintain and keep clean.

This aquarium boasts a modern style with a sleek, rounded-edge design. The tank itself is only 15 inches wide, so it won't take up a lot of space either. It has a 24-hour timer and LED lighting, which can be changed to different colors, including blue and white, and an automatic sunrise/sunset plus a moonrise/moonset feature so your fish and their environment get the added benefit of a natural day and night cycle.

This lighting functionality also allows live plants and corals to flourish in the tank. You'll still need to purchase a few essential accessories separately, such as a net and a thermometer, if you don't already have them on hand, but with all the features this aquarium has, that's no biggie in our books.

^{Dimensions: 16.75 x 15 x 17.5 inches | Gallon Capacity: 16 | Material: Plastic case with glass sides | Accessories: Filtration chamber, LED lights, timer, lid | Inhabitants: Small school, guppies, tetras, goldfish}

Best Budget

Tetra Crescent Aquarium Kit

$83

$79 at Amazon View on Petco View on Walmart

The Tetra Crescent Aquarium Kit is an acrylic tank. This material comes with some benefits and drawbacks. Acrylic is sturdier than glass and lighter. However, it can scratch easily and become cloudy over time. Please be sure to use only acrylic-safe scrub brushes (not included) when cleaning your tank.

With this tank, the included filter media is not durable and will break down relatively quickly. It is recommended to be replaced with a sturdier sponge. Given the lid included with this tank, it can be difficult to swap out for another filter if desired.

_{Dimensions: 17 x 11 x 13 inches | Gallon Capacity: 5 | Material: Acrylic tank with plastic top | Accessories: Filter, hood with light, setup guide | Inhabitants: Betta, small school}

Best for Shrimp

Aquatop Venti Aquarium Kit

$117

$110 at Amazon View on Aquatop.com

In a shrimp tank, water flow is critical. Shrimp can be very delicate invertebrates and require a very low water flow. That is why we recommend the Aquatop Venti Aquarium Kit, which is run entirely on an air-lift system.

An air-lift system uses the flow and circulation of bubbles through an air pump to drive its filtration. As you can imagine, this creates a tank with a very low filtration capacity, which is perfect for detritus-loving shrimp.

This kit includes everything your shrimp colonies could need, including a durable filter sponge, air pump, air line tubing with check valve, and a light. All you need is a shrimp-appropriate substrate and a few live plants or moss balls, and then you can add your shrimp.

_{Dimensions: 8 x 12 x 12 inches | Gallon Capacity: 2 | Material: Plastic case with glass sides | Accessories: Filter, air pump, air line, check valve, light, lid | Inhabitants: Shrimp}

Best Round Tank

biOrb CLASSIC MCR Aquarium

$153

$140 at Amazon View on Chewy $234 at Wayfair

This round tank from biOrb offers a design inspired by the classic fishbowl, but with additional features and connectivity that make it safe for fish and easy to maintain. The small tank has a streamlined base and lid and comes with a low-voltage pump and filtration system. Plus, the aquarium features multi-colored remote-controlled LED lights with adjustable day and night modes.

This freshwater acrylic aquarium is available in black or silver and in three sizes: 4-gallon, 8-gallon, and 16-gallon. Setup is easy, but the small opening does make it harder to clean and maintain—especially for adults with larger hands.

_{Dimensions: 12 x 12 x 12.5 inches | Gallon Capacity: 4, 8, 16 | Material: Acrylic tank with plastic top and base | Accessories: LED lighting, air pump, transformer, water treatments, air stone, filter cartridge, ceramic media | Inhabitants: Betta, small school, tropical}

Best No-Frills Kit

Aqueon MiniBow Small Aquarium Fish Tank Kit

$73 at Amazon $73 at Chewy

$77

$73 at Petco

If you have a small space, such as a desktop or nightstand, a no-frills option would be a smart choice. Aqueon LED MiniBow Kits come in 2.5- or 5-gallon options. The easy-care aquarium is simple to set up, and its low-key design means that it will fit into most decors. If you can't decide where the acrylic aquarium will live, it's easy to move—the 5-gallon option is only 5.25 pounds. The three-step water change procedure is fast and easy. Just be sure to replace the filter cartridges every four weeks to keep your small fish happy and healthy.

_{Dimensions: 14.5 x 10 x 13.5 inches | Gallon Capacity: 5 gallons | Material: Acrylic | Accessories: LED hood, filter cartridge, water care and food samples, setup guide | Inhabitants: Betta, small tropical}