6 Best Nano Aquariums

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Are you looking for the best nano aquarium? We’ve got you covered.

Keeping fish can be a stimulating and rewarding hobby. Aquariums come in all shapes and sizes, and you might think that bigger is better — but think again.

Beautiful things often come in small packages, and although nano aquariums are small, they can be even more beautiful, fascinating, and challenging than big tanks.

Want to know more about the scaled down world of nano aquariums? Read on…

What Is A Nano Aquarium?

In simple terms, a nano aquarium is an aquarium with a capacity of less than 20 gallons.

Small enough to fit perfectly in almost any room, they are designed to house plants, fish and / or invertebrates such as shrimp, or coral.

Keeping such a small tank can be a great idea for beginners, or for the more experienced fish keeper who can master how to keep things such as water temperature and chemicals balanced, it can be a challenging space to create an incredibly vibrant and infinitely interesting mini environment.

Stocking Ideas for a Nano Aquarium

How Many Fish Can Be Kept In A Nano?

nano fish tank

The number of fish that can be kept in a nano aquarium depends entirely on its size.

Very small tanks from 3 to 8 gallons are really only suitable for keeping invertebrates such as shrimp and snails, or just one beautiful Betta fighting fish.

Tanks with a capacity of 8 to 20 gallons open up more possibilities, but it’s not just about how many fish you can keep in a nano aquarium, but also what type.

Generally it’s better to select smaller, non aggressive fish species, and aim for no more than one small fish no more than 1 inch long when adult per gallon of water, or if the fish species is a little larger — 2 inches for example — then no more than one fish per 2 gallons of water.

This means that in a 10 gallon nano you could have either 10 small fish, or 5 slightly larger fish living together.

Best Plants For A Nano Fish Tank

Plants can make all the difference to a nano aquarium. They provide color and texture, and help keep tank water clean, oxygenated and chemically balanced.

Tiny tanks means tiny plants. Whenever possible try not to crowd the tank to leave more room for the fish, and plant taller plants behind shorter ones to add depth.

Here are our top 5 favorite plants for a nano aquarium…

Anubias Nana

best plants for nano aquarium
By Tsunamicarlos (Public domain)

There are many different varieties of this dwarf aquatic plant that grows to no more than about 5 cm in height.

They are compact and slow growing, have a pleasant green, leafy appearance and are very simple to care for.

Anubias Nana don’t require much sunlight, and prefer a water temperature of between 65°F and 85°F, plus a pH of between 6.5 and 7.5.

They root easily whether into the substrate or attached to driftwood or other aquarium furniture, and look great when placed in the foreground.

Christmas Moss

best plants for nano fish tank
By Storm (CC BY-SA licence)

Christmas Moss — aka Vesicularia montagnei — is a lush ground cover plant which grows in dense clumps and resembles miniature Christmas trees.

This pretty plant can be either free floating or attached to the aquarium walls or furniture, or attached to a mesh placed on the substrate.

Christmas Moss grows fairly happily at most pH levels, but prefers medium to bright light levels.

Staurogyne Repens

plants for small fish tanks
By Lennart Jöhnk (CC BY-SA 4.0 licence)

If you’re looking for a mid-ground plant for your nano tank, Staurogyne Repens is an excellent choice.

It can grow to a height of up to 10 cm in attractive, bushy bunches of green leaves.

It’s fairly easy to care for too, although it does grow best in an environment with a lot of light at a temperature between 68°F and 82°F, and a pH level between 6 and 8.

Dwarf Hairgrass

best plants for small fish tank
By Andrey Zharkikh (CC BY 2.0 licence)

Eleocharis parvula — or Dwarf Hairgrass — is a fantastic carpeting plant which resembles a tiny lawn growing in the substrate at the bottom of your aquarium.

It’s a great plant for beginners as it is hardy and easy to grow and care for, and if you care for it correctly it will reward you with colorful miniature flowers.

Dwarf Hairgrass is slow growing so it won’t take over a small space, and grows to a maximum height of 4 inches.

This aquarium plant prefers a moderate to large amount of light.

Cryptocoryne Parva

Best plants for nano aquarium
By Carnat Joel (CC BY 2.0 licence)

Capable of growing to a height of 10 cm, Cryptocoryne Parva is ideal as a mid to background plant. It has long green leaves and grows very slowly, which is a huge positive point for a nano aquarium plant.

Easy to look after, Cryptocoryne Parva isn’t fussy about growing conditions and long as it is planted into a nutrient rich substrate in water of between 65°F and 84°F, and gets a good amount of light.

Freshwater Nano Tank

When stocking a freshwater nano aquarium there are a ton of possibilities.

For tanks with a capacity smaller than 8 gallons, there are a wide variety of brightly colored dwarf shrimp, and crayfish which do particularly well, but for aquariums with between a 8 and 20 gallon capacity there are many interesting fish species that are well suited to a freshwater nano tank.

Gouramis, pea puffer fish, tetras, certain species of cichlid, pygmy corydoras, mollys and platys are just some of the many smaller freshwater fish that can be kept fairly easily, although care must be taken to avoid putting certain species together as some such as certain gouramis and killifish can be aggressive.

best nano aquariums

Saltwater Nano Tank

Marine nano aquariums need to be carefully tended in order to thrive, but it’s nevertheless possible to create a truly magical miniature underwater world. Invertebrates such as pistol shrimp or fire shrimp are a good choice, as well as certain small corals such as leather and mushroom corals, galaxy coral and star polyps.

Firefish and neon gobys are two species of active, colorful fish that suit small tanks well. Clownfish are a popular choice, the stunning purple and gold royal gramma fish and the aptly named dwarf pygmy coral beauty angelfish are peaceful and provide amazing vivid color.

Blue and green chromis are attractive and thrive in small groups, and it is even possible to keep dwarf seahorses, although these cannot be kept alongside fish.

How To Set Up A Nano Aquarium

There are many different kinds of Nano aquarium set up — from the smallest and most simple shrimp or betta tanks, through larger freshwater tanks and complex salt water tanks — but whatever type of nano tank you choose, it will need the same basic elements in order to create a healthy living environment.


To keep tank water clean and ensure a constant flow of fresh water it is essential to have a filter.

Filters work to cleanse water of impurities such as fish waste products, excess food, dangerous chemicals, and decaying organic matter.

They are available in two different styles; external filters which hang on the back of the tank, or internal filters that are submerged within the tank itself.


Fish and plants need light to grow and be health, and mimic the natural day and light cycle, as well as enhancing the colors of your fish.

Unless your nano aquarium comes with a light already built in you will need to set up a separate light.

The type of aquarium light needed for any size of nano tank depends on which fish and plants you wish to keep and what you intend the final to be.


Tropical fish and plants need higher water temperatures to survive as they cannot regulate their own body temperature.

In a nano aquarium, a heater performs the function of warming up the water to the correct temperature to keep fish and plants healthy.


At least 1 inch of gravel, sand or other appropriate substrate material must be put at the base of your tank.

The substrate provides a place for beneficial bacteria to grow which biologically filter the tank water, as well as providing a more comfortable environment for fish.

If you decide to place aquatic plants in your nano aquarium, the substrate provides them with a nutrient rich place where they can root easily and grow healthily.

What Other Equipment Do You Need?

Any other equipment you decide to put in your nano tank is down to personal choice, as well as what kind of tank you have.

Adding a hardscape for example not only looks attractive, but also provides a place for fish and other animals to hide and explore.

In the case of salt water aquariums, additional equipment may be required such as a refractometer or hydrometer to measure water salinity, chemicals such as ammonia or trace elements including calcium, magnesium, and alkalinity to ensure tank water keeps the correct chemical balance.

Live rock can also be a useful addition as it is already an established system with beneficial bacteria, organisms, and other live elements.

The Best Nano Aquariums

Marineland 5-Gallon Portrait Aquarium Kit

best small aquarium

This simple 5 gallon nano aquarium by Marineland features a tall, portrait style tank with convenient sliding glass hood which provides easy access to the interior.

The filter has an adjustable pump and is neatly concealed behind a back panel, so there is nothing on show to spoil the tank aesthetic.

It also features 2 stylish LED light options; white to recreate the effect of sunlight, and blue to induce a soothing, moonlight effect.


  • Quick and easy to set up
  • High quality
  • Nice light settings
  • Elegant design
  • Effective 3 stage Bio Foam filtration system
  • Easy to maintain


  • No heater included
  • Filter flow may be a little strong

best nano aquarium

Hygger Horizon 8 Gallon LED Glass Aquarium Kit

hygger horizon 8 reviewbest nano aquarium

The attractively designed Hygger Horizon 8 Gallon LED Glass Aquarium Kit for Starters features a curved front and comes with an attached rocky resin backdrop which provides a fantastic, fun environment for your fish.

The backdrop cleverly hides the 7W internal carbon fiber and moss filter and pump. 18W LED lighting features 3 different colored light modes with adjustable brightness — white, blue and red, or a combination of all 3 colors — and can be set to operate using a timer.

This base of this nano aquarium measures 19 by 11.8 inches, with a height of 9.6 inches.


  • Hidden filter system
  • Easy to clean and maintain
  • Practical clear top panel
  • Gives a wide, clear view of your fish
  • Quiet filter
  • Filter functions even when water levels are low


  • Capacity is reduced to 6 gallons because of fixed rocky backdrop
  • Filter could be more powerful

best nano aquarium

Fluval Edge Aquarium with LED Light

fluval edge reviewbest small aquarium
The clever design of the glass, 6 gallon Fluval Edge Aquarium with LED Light allows for an almost 360° view of your underwater nano world.

This is made possible due to the innovative pedestal design which supports the tank around the middle, and houses the 3 stage filter, pump, and LED lights, and is also due to the sealed glass top which has the added benefit of reducing water evaporation.

The filter uses a combination of a mechanical filter for debris, a chemical filter for unwanted chemicals, and biological filter for bacteria to best purify water, and the 21 LED lights can be switched to white for daytime, blue for night time, or turned off completely.

This nano aquarium is also available in a 12 gallon capacity.


  • Stunning design
  • All functional elements are completely hidden
  • Compact size
  • Additional room for extra filters if required
  • Powerful, quiet filter
  • Night and day lighting options


  • A little tricky to clean and maintain
  • Somewhat expensive

best nano aquarium

Fluval Spec III Aquarium Kit 

fluval aquarium review

Truly tiny, the Fluval Spec III Aquarium Kit has a 2.6 gallon capacity is conveniently sized to fit neatly into the smallest of spaces.

Measuring just 11.8 x 10.8 x 8.7 inches, this small and stylish nano aquarium doesn’t compromise on features.

The powerful pump and filter system uses 3 tier filtration to eradicate biological waste, nasty chemicals, and harmful bacteria from the tank water, and the system is neatly concealed and separate from the tank itself, making it simple to maintain.

The minimalist hood design boasts 31 LED lights to perfectly illuminate the aquarium environment.


  • Great size for betta or shrimp
  • Attractive design
  • Small footprint is ideal for desk or table placement
  • Made from durable glass
  • Easy to set up
  • Low maintenance


  • Lighting is only one color and not very bright
  • Filters could be more effective

best nano aquarium

Tetra LED Cube Shaped 3 Gallon Aquarium

best small aquarium

Great for beginners, the Tetra LED Cube Shaped 3 Gallon Aquarium is constructed from acrylic and has a simple yet attractive pedestal design which allows you to see your tank from any angle.

The supplied Tetra 3i filter provides excellent mechanical and chemical filtration, and the LED light illuminates the tank interior brightly.

Measuring just 10 inches deep by 10 inches wide and 10.5 inches high, the Tetra LED Cube Shaped 3 Gallon Aquarium can fit unobtrusively almost anywhere in the home or office.

Fish can be fed through the handy feeding hole in the tank lid.


  • Great value
  • Easy to set up and maintain
  • Pump and filter run quietly
  • Filter flow is adjustable
  • Lightweight


  • Acrylic may scratch if not handled carefully
  • LED lights cannot be adjusted

best nano aquarium

Aqueon Betta Falls Kit

best nano aquarium

Designed specifically with beautiful bettas in mind, the Aqueon Betta Falls Kit has a stunning 3 tiered appearance with 3 separate curved compartments at staggered levels, which creates the possibility of keeping 3 male bettas or other fish or invertebrates in the same aquarium.

Frosted panes in between each compartment prevent triggering stress or aggression as they can’t see one another.

The filter and pump are hidden away at one end of the tank, and they create a cascading waterfall that feeds all 3 compartments with freshly filtered water.

This nano aquarium measures 16.9 inches in length, 4.92 inches in width and 11.15 inches in height, and can be combined with up to 2 other Aqueon Betta Falls Kits to create a sensational circular display. Optional hoods are included in the kit.


  • Beautiful appearance
  • Compact
  • Waterfall flow is adjustable
  • 3 tanks in one
  • Effective filtration
  • Easy to set up and maintain


  • Fish may use the waterfall flow to slip from one tank to another
  • No heater or lights included

best nano aquarium

What’s your choice for the best nano aquarium?

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