Finding the right fish for your freshwater nano tank can be quite the task. One wrong fish can throw off the ecosystem entirely.

A regular sized Chinese Algae Eater, for example, would probably not be a good idea. As you can already imagine, fully grown it would thrash about any nano-tank, wreaking havoc upon the other fish in this small environment.

As any experienced fishkeeper knows, just because a tank is smaller, doesn’t mean that it requires less attention. So, new fishkeeping enthusiasts be warned.

Smallest Freshwater Aquarium Fish Video

The good news is that once you do settle on the right fish, a well-populated nano tank can look great anywhere. It is not uncommon to see a beautiful nano tank on a desk at work or in your home, serving as both a pleasant sight and a source of natural inspiration throughout the day.

So, without further ado, let’s take a look at the best freshwater aquarium fish for nano tanks.

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1. Ember Tetra

Hyphessobrycon amandae (5)

Care Level: Minimal
Max Size Of Fish: 2cm
Temperature Range: 73-84F
PH Range: 6.6

These Brazilian freshwater fish make for great tank mates. Their beauty is striking, being mostly red and orange with slightly translucent bodies.

Nano tanks with a decent amount of live plants are great for Ember Tetras they will enjoy swimming and relaxing in the plants.

What a lot of people don’t know about Ember Tetras, is that they prefer acidic water. They are also most comfortable in decently planted environments.

Aside from that, they’re fairly easy to maintain.

They prefer to be in the company of a group. In terms of diet, they enjoy a mix of flakes and dried goods. Some live foods can also be given to Ember Tetras, such as brine shrimp.

2. Pea Pufferfish

Dwarf Pufferfish

Care Level: Medium
Max Size Of Fish: 1.4in
Temperature Range: 77-79F
PH Range: 7-7.8

The Pea Pufferfish, also known as Pygmy Pufferfish, is a small species of pufferfish native to Southwest India. In recent years, many pet stores and aquariums have seen the addition of these fish. Because of how small they are, they fit into nano tank environments well.

Unlike Marine Pufferfish, Pea Pufferfish live exclusively in freshwater.

Pea Pufferfish may show aggression at times, and this is something to keep in mind. They are also quite carnivorous, and will even prey upon live snails small enough to eat. Although they will eat some plant-based flakes, they prefer a meatier diet that includes insects and worms.

3. Sixray Corydoras

Corydoras trilineatus

Care Level: Medium
Max Size Of Fish: 1.1in
Temperature Range: 72-77F
PH Range: 6-7.2

Sixray Corydoras will rarely exceed an inch in size, making them ideal for nano tanks. Their origin is South America, mainly Brazil.

Technically, there are hundreds of corydoras species, many of which are unnamed. They are natural bottom feeders, enjoying both a meat and plant-based diet.

The Sixray Corydora prefers an aquatic environment that mimics a tropical setting. Like other fish on this list, aquariums with decent vegetation are ideal to conceal their fry.

4. Scarlet Badis


Care Level: Medium
Max Size Of Fish: 2cm
Temperature Range: 75-79F
PH Range: 6.5-7.6

In terms of size and looks, Scarlet Badis are as close to perfect for nano aquariums as possible. Though small, these fish can sometimes be aggressive, but mostly toward their fellow males.

Females have a tendency of being about 0.7 cm smaller than males on average. Males have a unique ventral fin, making them easy to identify.

The main thing to keep in mind when dealing with Scarlet Badis is that they are naturally predatorial.

Tanks containing a variety of objects like live plants and decorations are great for preventing tensions from escalating. Reason being is that these objects will cut off any clear line of sight, that may be a pathway toward aggression

5. Hara Jerdoni


Care Level: Difficult
Max Size Of Fish: 1.5in
Temperature Range: 64-75F
PH Range: 5.6-7.6

Hara Jerdoni fish were originally found in India. The Hara Jerdoni is among the tiniest species of catfish, perfect for nano tanks.

These whiskered, bottom-dwelling fish are cute and for the most part inactive. They are content in small tanks and are not desperate for additional room to roam.

They tend to remain in the same location for the majority of the day, making them a friendly companion to other fish. However, their solitary nature doesn’t mean that they don’t require care. Tanks with above-average oxygen levels are ideal for these fish.

Forming the right habitat is the hardest part when looking after Hara Jerdoni fish. These smaller catfish prefer tanks with some form of cover, under which they can lounge for hours.

Basically, Hara Jerdoni tanks should be supplied with hiding places galore:

Although they can be alone, the company of a group is preferred. They are nocturnal and come feeding time, they will eat a variety of live, frozen, and dried foods including shrimp and worms.

6. Pygmy Corydoras

Pygmy Corydoras

Care Level: Minimal
Max Size Of Fish: 1.3in
Temperature Range: 72-79F
PH Range: 6.5-7

Known for getting along well with Ember Tetras, Pygmy Corydoras are active and friendly fish. They can be quite social and warm toward other small, nano-tank friendly fish. They also live well among various shrimp and water snails. Pygmy Corydoras are a mid-dwelling fish, preferring to roam about a tank in shoals.

Their colors, although not overly loud, suit them well. They are primarily silver-bodied, with a confident, unbroken black streak running from their mouth to their caudal fin. These calmer color patterns can easily balance out a tank.

Interestingly, Pygmy Corydoras fry can be distinguished from adults by identifying whether or not their black streaks are horizontal or vertical. Adults have horizontal black stripes, while the young will display vertical stripes.

Pygmy Corydoras are known for being relatively easy to care for. Females produce a large number of eggs, usually around 100. As far as diet, anything that sinks is fair game for Pygmy Corydoras. A variety of flakes, and even sinking wafers, make for good meals.

It is always best to surround Pygmy Corydoras with non-aggressive fish.

7. Salt And Pepper Catfish

Peppered Catfish

Care Level: Minimal
Max Size Of Fish: 1.3in
Temperature Range: 75-78F
PH Range: 5.5-7.5

Salt and Pepper Catfish are a South American tropical species. Being native to tropical environments, they are commonly seen in wetlands. The shallow waterways that they prefer, are often dangerous to their populations, as they are likely to dry.

Salt and Pepper Catfish are known for taking leisurely swims to the surface for gulps of air. Although this is normal for this species, if other fish in a nano tank are also doing so, it could be a sign of low oxygen levels.

Salt and Pepper Catfish thrive in groups and enjoy different types of flakes and pellets. Brine shrimp are considered a favorite. Their aquarium environment should be somewhat dense with plants and leaves, modeled after the tropical conditions they’re used to.

8. Endlers Guppies

Endler Guppy.

Care Level: Minimal
Max Size Of Fish: 1.8in
Temperature Range: 75-81F
PH Range: 5.5-8

Endlers Guppies are ideal nano tank mates. These guppies are beautifully colorful. Although they are similar to regular guppies, they have been given different names for the sake of their own population, which sadly, is nearing extinction.

They’re very active and have even been known to keep algae levels low in some tanks.

Known for being fearless, Endlers Guppies are willing to become familiar with just about anything. No areas of a nano tank are considered off limits, in the mind of an Endler Guppy. Even during tank water changes, they are known for their curious investigations.

Like most guppies, they thrive in warm water, especially for growth. Tank covers are essential because jumping is one of their strong suits. They enjoy a variety of foods. Bloodworms are an Endler Guppy delicacy. Plants are also essential, especially as cover for their fry. They get along well with other fish, posing no threat, and will often engage in playful behavior.

9. Sparkling Gouramis

Sparkling Gourami

Care Level: Medium
Max Size Of Fish: 1.6in
Temperature Range: 77-83F
PH Range: 6-7.5

Sparkling Gouramis are truly a fish of beauty. Their red, blue, and green sparkles allow them to stand out gorgeously within nano tanks. They are shaped like miniature arrowheads.

Aside from poor choices for companions, they are known for being somewhat forgiving in less suitable tank environments. This is partly due to their labyrinth organ, an organ that makes life easier for new aquarists. The labyrinth organ enables the Sparkling Gourami to engage in an alternative breathing technique, compared to most fish. This gives them the chance to breathe at surface levels, which they often take advantage of.

These Sparkling Gouramis like all kinds of foods, and a diet consisting of a mixture of frozen and live foods is ideal. Live foods such as bloodworms and brine shrimp are savored by Sparkling Gouramis.

The only difficulty they present is the need to find the right tank mates. Bettas, especially males, can create issues for Sparkling Gouramis.

10. Licorice Gouramis

licorice gourami

Care Level: Minimal
Max Size Of Fish: 1.3in
Temperature Range: 74-82F
PH Range: 5.6-7.2

Like Sparkling Gouramis, Licorice Gouramis are also some of the tiniest freshwater Gouramis, making them a dream come true for nano tank enthusiasts. They are beautiful to behold, displaying primarily black and silver color patterns.

In terms of setting, the Licorice Gourami does enjoy a fair amount of shade. This is where driftwood and a few live plants can come in handy. Licorice Gouramis are peaceful tank mates, that enjoy both meaty and plant-based treats.

Being a gentle fish, Licorice Gouramis prefer the company of other good-natured creatures. Proper nano tank filtration should be maintained, in order for Licorice Gouramis to thrive. In contrast with most labyrinth fish, surface breathing is less common. Like other Gouramis, slightly acidic water goes a long way.

11. Green Neon Tetra

Green Neon Tetra

Care Level: Minimal
Max Size Of Fish: 1.3in
Temperature Range: 75-84F
PH Range: 5-7.8

Not to be confused with the Neon Tetra, Green Neon Tetras are great freshwater fish that are the ideal size for nano tanks. Their reds are quieter than the Neon Tetra’s, but their blue-green regions are more defined. Although slightly less colorful than other popular tetras, they make up for it by being the perfect size for nano tanks.

Green Neon Tetras are beautiful in appearance, and generally peaceful to other fish. They prefer a mixed diet, consisting of a wide variety of live foods and pellets.

Before purchasing a Green Neon Tetra, it’s good to read up on Neon Tetra Disease, which attacks Neon Tetras from the inside out. One of the main signs is white patches. Unfortunately, a cure for this parasitic affliction has yet to be discovered.

12. Neon Tetra


Care Level: Minimal
Max Size Of Fish: 1.3in
Temperature Range: 70-77F
PH Range: 6-6.5

Neon Tetras are some of the most beautiful fish available to beginner aquarists. They prefer tropical aquarium environments, that mimic what they have adapted to in nature.

They are a mid-level fish. Possessing a faint-hearted temperament, Neon Tetras will get along great with other fish their size. With diet, Neon Tetras will usually accept a wide variety of dried flake foods.

At times their color may fade. This is usually a sign that they are under some form of stress. Unfortunately, aquarium settings usually cut their lifespans in half (from 10 to 5 years).

Final Thoughts

Nano tanks can make for absolutely beautiful aquariums. Most new aquarists make the mistake of believing that because of their size, they are somehow easier to maintain.

Unfortunately, these aquariums are often marketed as being the easy choice, for those new to the hobby. This is simply not realistic, and those who do come to realize this can quickly become overwhelmed.

With that said, they are less daunting in terms of appearance, which can be appealing. In the right hands, they make for truly lovely tanks. The key factor, of course, is information. With the right information and care, any nano tank environment has the opportunity to excel!

What fish can you keep in a nano tank?

To recap here are just a few fish you can keep in your nano tank

  • Ember Tetra
  • Pea Pufferfish
  • Sixray Corydoras
  • Scarlet Badis
  • Hara Jerdoni
  • Pygmy Corydoras
  • Salt And Pepper Catfish
  • Endler Guppies
  • Sparkling Gouramis
  • Licorice Gouramis
  • Green Neon Tetra
  • Neon Tetra

What is considered a nano tank?

A Nano tank is a very small tank or aquarium used for fish, plants or other invertebrates. Typically the size of a Nano tank would be anything smaller than a 10-gallon tank.

101 Best Freshwater Nano Species
Fluval Nano LED Aquarium Light
Sunken Gardens: Guide to Planting Freshwater Aquariums
Small Catfish For 10 Gallon Tanks
Small Algae Eaters
Sponge Filters For Small Tanks

Links To Amazon