An aquarium hobby can take up a lot of space, but small and nano aquariums offer options that can work for a small space. In this guide, we’ll show you exactly what you need to keep your fish healthy without a large tank. To keep fish happy in a smaller space, advanced planning is the best tool at your disposal.
It's also crucial to understand a small tank's limitations. Many first-time fish owners start out with a small aquarium, then overstock it with too many animals. This not only leads to a lower quality of life for your new pets, but can even result in an ammonia spike that leads to a complete tank wipeout. This is one reason people never get further than that first aquarium.
Aquatic veterinarians understand how overstocked aquariums can easily lead to issues that can be solved with just a little more water and patience. As such please keep in mind that our recommended tanks are only suited to bettas, small schools of fish—such as neon tetras—or shrimp. In our recommendations, we’ll share which tanks are suitable to which species groups.
Our favorite small aquarium for most people is the Fluval Flex 9-gallon Aquarium Kit, which includes everything your new betta, shrimp or school of small fish needs for a long and stable life. But there are other small fish tanks we recommend that might work even better for your space.
Fluval Flex Aquarium Kit
Fully integrated lights and filtration
Durable filter media
Dedicated heater space away from main tank
Curved side can be a little harder to clean
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 that tucks into the back of the aquarium with pockets for both zeolite and carbon, which you can use if you want or remove them. These sponges will last you for years and never need to be replaced. They are easily accessed and there is every room for a 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.
Price at time of publish: $110
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
Fluval Spec Aquarium Kit
Fully-integrated filter media
Can pivot filter flow return
Filter intake can be a little strong for more delicate fish
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 up 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 plants may not be able to subsist on your fishes’ waste alone, so you may need to look into some fish-safe aquatic plant fertilizer.
Price at time of publish: $116
Dimensions: 21 x 8 x 12 inches | Gallon Capacity: 2.5 or 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
Fully integrated filtration and heater
Designed with betta fish in mind
Durable filter media
Water diffuser to decrease filter return to put less stress on bettas
Bettas love laying against the intake
Has a lid (bettas like to jump!)
Only 2.6 gallons
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, our Best Nano tank choice, 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!
Price at time of publish: $100
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
Fluval Vista Freshwater Aquarium Kit
Fully comprehensive kit
Great starter tank
Included food not recommended
Stick on thermometer not recommended
The Fluval Vista Freshwater Aquarium Kit is not only an 8.5 gallon glass tank, but also an all-in-one kit that's perfect for the first-time aquarium owner. It includes a highly rated filter, water conditioner, integrated hood light, bacterial starter, a stick-on thermometer, a soft net, start up guide and even a few fish food flakes. This is an awesome kit to get started with a few neon tetras, guppies or betta (they even have pictures on the box).
The only things you will need to add are a few cleaning tools (glass cleaner, gravel siphon), a heater (if your fish need one), and some fish. Everything included in the kit is useful and high quality, though we would recommend swapping out the stick-on thermometer for an in-tank one. The included fish food isn't all that useful either—look for fish or shrimp pellets instead.
Price at time of publish: $178
Dimensions: 20 x 10 x 12 inches | Gallon Capacity: 8.5 | Material: Plastic case with glass sides | Accessories: Filter, light, bacteria starter, water conditioner, thermometer, net, fish food, starter guide | Inhabitants: Betta, small school, shrimp
Tetra Crescent Aquarium Kit
Includes lighting and filtration
Lighter acrylic tank
Acrylic easily scratched
The light is small
The Tetra Crescent Aquarium Kit is the only acrylic tank on our list, which comes with some benefits and drawbacks. Acrylic is sturdier than glass and lighter. However, it can scratch easily and can become cloudy over time. Please be sure to use only acrylic-safe scrub brushes when cleaning your tank (not included).
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.
Price at time of publish: $54
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
Very mild water flow
Includes all filtration components
Intelligent design for shrimp
Should only be used for shrimp tank
Very limited filtration capacity
When dealing with 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 that is run entirely on an air-lift system. An air-lift system utilizes the flow and circulation of bubbles through an air pump to drive its filtration. As you can imaging, this creates a tank with a very low filtration capacity, which is perfect for your 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, a few live plants or moss balls to enjoy and then you can add your shrimp.
Price at time of publish: $80
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
When it comes to choosing a small aquarium, we recommend the Fluval Flex 9-gallon Aquarium Kit, which is well thought-out and designed to be a great fish home in a small space. If you do not have room for even a 9-gallon tank, our favorite nano tanks is the Fluval Spec 5-gallon aquarium, which has a small footprint but is still suitable for bettas, shrimp, or more, as long as you plan carefully. As with any small tank, take into consideration what type of fish and how many you plan to accommodate. If you can go bigger, get a bigger tank!
What to Look for in Small Fish Tanks
When it comes to any aquarium, ensuring there is enough water and space to go around will be determined by your bioload. Your bioload is the total amount of living things in your tank, including all fish, invertebrates and down to the tiniest bacteria. Some fish tend to not convert food to body mass well, such as goldfish, and produce a lot of waste, adding more to your bioload. They also require a ton of space compared to a small school of neon tetras. Small tanks can be very tricky if you try to cram too many species into a small space.
Glass vs. Acrylic
For all aquariums, regardless of size, you will need to select a material for the sides of your tank, depending on your preference. Glass is more delicate, heavier, but easier to clean and will stay clear for longer. Acrylic is more durable and lighter, but can be easily scratched and will become cloudy over time. Since the aquariums we are discussing here are so small, it is recommended to go with glass since they hold less water (lighter) and easier to ship padded (less breakable). When we were doing research for this article, I could not find many acrylic aquariums that were appropriate for fish in a small size.
Additional Equipment and Accessories
For any aquarium, you should consider the following accessories:
- Lid for tank
- Aquarium light
- Substrate (gravel, rocks, sand, etc.)
- Gravel vacuum
- Decor items (must be fish safe)
- For bettas, stick with items that will not snag fins
- Live plants
- Dechlorinator/water conditioner to treat tap water for chlorine and chloramine
- Scrub brush for decor
- Algae scraper for acrylic or glass tank (be sure not to mix them up, as they are different)
- Heater (for certain species)
- Water quality test kit
What fish can live in a small fish tank?
Small fish tanks should be kept exclusively for small, tropical fishes, including neon tetras, bettas or rasboras. Fish that should not be kept in small tanks include goldfish, guppies/mollies (unless you can guarantee you only have one sex), or cichlids. Small ornamental shrimp are also a good candidate for a small aquarium.
How often should you clean a small fish tank?
Like any other fish tank, you should expect to do some maintenance every week. This may include trimming plants, cleaning the side of your aquarium or rinsing your filters. You will still need to use a gravel siphon to do water changes, just choose a size appropriate for your tank. Take special precaution when using this around shrimp!
How many small fish can I keep in a 10-gallon tank?
It depends entirely on the species. For small tropical fish, some may like to be in a school of 8-10 individuals, while others like to be alone, such as bettas. Depending on the species you choose, you may look into a mixed-species tank, choosing individuals who are community-minded and will get along with multiple species.
Do fish bowls work well as a small aquarium setup?
Absolutely not. Fish bowls are antiquated and should not be used for any living thing.
Why Trust The Spruce Pets
With over 10 years’ experience in pet fish veterinary practice, not to mention owning her own aquatic specialty store for 3 years, Dr. Jessie Sanders has seen it all when it comes to fish tanks. She has firsthand experience with all major pet species and understands what goes into keeping them happy and healthy with all the tanks and equipment available to pet fish owners. She has personal experience with most of the tanks on this list, having set up several for her own practice and helping hundreds of pet fish owners keep their fish happy and healthy.