While large aquariums can certainly look majestic, small tanks stocked with nano fish can look equally spectacular, with the added bonus of being easier and cheaper to maintain.
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There are over a hundred small fish species that can be housed in compact tanks, but it can be difficult to choose, especially as you need to consider the care requirements of the fish, as well as your tank setup and experience level.
I was pretty indecisive when I started my first small aquarium 7 years ago – it actually took me two months to stock it after fully cycling it! That’s why I’ve compiled a list of some of the best nano fish to help you narrow down your options and select the right one for your tank.
Top 12 Nano Fish For Your Aquarium
Celestial pearl danios are a lively freshwater fish with a striking speckled appearance. They love to be kept in groups and are fairly easy to keep.
Celestial Pearl Danio
The celestial pearl danio, also known as the galaxy rasbora, is a brightly colored fish with red fins and a blue body covered in tiny spots that resemble pearls (hence the name). They reach around 1 inch in length, which makes them one of the best nano aquarium fish.
Celestial pearl danios are schooling fish originally from Southeast Asia, so they should be kept in groups of at least 6. For this reason, a minimum tank size of 10 gallons is necessary for this species. They can be extremely timid, so try to make sure your tank is heavily planted and has lots of hiding places like rocks to make them feel more secure.
Compatibility
This species is relatively hardy and has a peaceful temperament, making them a good option for new fishkeepers. You can house them in community tanks with other passive species, including pygmy corydoras, fancy guppies, dwarf shrimp, white cloud mountain minnows, Asian stone catfish, and most tetras.
Galaxy rasboras are omnivores and will readily accept freeze-dried, live, and frozen fish foods. Personally, I feed my group crushed fish flakes (pellets targeted for small fish will also work), baby brine shrimp, daphnia, bloodworms, and the occasional veggie.
Ideal water parameters for these micro fish are a pH of between 6.5 to 7.5, a temperature of 73°F to 79°F, and water hardness within the range of 2 to 10 dKH.
Specs
- Size: 1 inch
- Care Difficulty: Easy
- Required Tank Size: 10 gallons
Ember tetras are one of the smaller fish species in the tetra family, only reaching a maximum size of 0.8 inches (about the length of a cherry). They boast a vibrant orange-red color and have a peaceful temperament.
Ember Tetra
The ember tetra is a peaceful shoaling fish that only grows to 0.8 inches in length, making them a great pick for small tanks of 10 gallons and above. They are a stunning orange-red color, which looks particularly striking in densely planted aquariums.
Temperament
Due to their docile nature, they can be housed with other fish such as the fancy guppy, chili rasbora, harlequin rasbora, pygmy corydora, and other tetras like the cardinal tetras.
These little fish can be quite shy, so they do best in large groups (at least 6) in heavily planted nano tanks. Although relatively hardy once established in an aquarium, ember tetras can be sensitive to poor water quality and improper water parameters.
Water Requirements
In order to keep these fish comfortable, your nano aquarium should have a pH level of between 5 to 7, water hardness in the range of 5 to 16 dGH, and a temperature between 73°F to 84°F.
Ember tetras are omnivores, so they will eat both meat-based foods and some plant matter. Make sure you give them a variety of freeze-dried, live, and frozen food to keep them healthy, including flake food, baby brine shrimp, daphnia, and vegetables like spinach and zucchini.
Specs
- Size: 0.8 inches
- Care Difficulty: Moderate
- Required Tank Size: 10 gallons
Betta splendens are stunning nano fish that typically don’t exceed lengths of 3 inches. They have straightforward care and unique personalities, making them a great pick for those new to fishkeeping hobby.
Betta Fish
It would be hard to compile a list of the best nano fish without mentioning the beautiful betta. Siamese fighting fish or betta fish are by far the most popular freshwater fish for a small tank due to their small size (they only reach 2 to 3 inches in length!), inquisitive personalities, and stunning appearance.
Bettas come in a vast number of colors, patterns, and tail types, all of which look truly breathtaking. My current betta is a red crowntail called Cinnamon and he’s the friendliest fish I’ve ever owned – he’s always quick to greet me (and beg for food!) whenever I walk past his tank.
Water Requirements
They make great beginner fish as they are hardy and can tolerate poor water quality slightly more than some other fish. Aim to keep this species in at least a 5-gallon tank with a temperature of 75° to 81°F, pH of 6.5 to 7.5, and water hardness between 3 to 5 dKH.
NOTE
It’s important to cover the betta tank with a lid as bettas have a tendency to jump out of the water.
Siamese fighting fish are carnivores, so they require a high-protein diet. Offer them a variety of freeze-dried, live, and frozen foods like high-quality fish flakes or pellets, tubifex micro worms, brine shrimp, bloodworms, and mosquito larvae.
Bear in mind that siamese fighting fish are notoriously aggressive towards their own kind, especially male bettas, so they should be housed alone. Female sorority tanks can sometimes be successful, but there is no guarantee that the fish will always be tolerant of one another.
Specs
- Size: 2.5 inches
- Care Difficulty: Easy
- Required Tank Size: 5 gallons
Neon tetras are a staple in the aquarium hobby due to their bright colors, peaceful temperament, and simple care.
Neon Tetra
Another beautiful freshwater fish for small aquariums is the neon tetra, one of the most popularly owned fish in the tetra family. The wild form color of the neon tetra is red, blue, and silver, but other varieties are also available, including black, gold, albino and green neon tetra.
Although all beautiful in their own way, I can’t help but like the classic red and blue neon the most – they look gorgeous in a planted tank and really light up the environment!
Size
Neon tetras are small fish that only reach around 1.5 inches in length, so they are suitable for nano aquariums of at least 10 gallons (ideally 20 gallons as they are quite lively!). Like most tetra species, neons are schooling fish and prefer to be housed in numbers of at least 6.
You’ll find that they are much more active and outgoing when housed in large groups, so bigger nano tanks are recommended for this species. Make sure your aquarium contains plenty of live plants to provide these tiny freshwater aquarium fish with shelter and hiding places.
Compatibility
Neon tetras are peaceful community fish and can be kept with many nano fish species, including betta fish, pygmy corydoras, fancy guppies, platies, dwarf puffer fish, cardinal tetra, and chili rasbora.
The ideal setup for this shoaling fish is a planted tank with a pH between 5 to 7 (can live in slightly acidic water), water hardness between 2 to 10 dGH, and a temperature around 68° to 78°F.
As omnivores, neon tetras can be fed small fish flakes, frozen and live foods, and vegetables like peas, spinach, zucchini, and cucumber.
Pros
- Size: 1.5 inches
- Care Difficulty: Easy
- Required Tank Size: 10 gallons
The fancy guppy is a peaceful fish that looks beautiful in a nano tank, especially when kept in groups. They come in many different colors and patterns, and only get to between 1.5 to 2.5 inches in size.
Fancy Guppy
Guppies are a small freshwater aquarium fish that make a wonderful addition to any nano aquarium thanks to their vibrant colors, passive nature, and playful personalities.
These fish come in a wide number of colors and patterns, including blue, red, black, yellow, green, and purple, but male fish tend to be more vivid and have longer tails. I personally love the half black guppy – its shimmery scales and dark coloration looks like the night sky!
In addition, males normally only reach around 1.5 inches in length, whereas females can grow as large as 3.5 inches. Guppies are social fish, so they thrive in groups of at least 3. The minimum tank size for this fish is 5 gallons for a trio, but bigger is always better.
Compatibility
Guppies are one of the most peaceful fish you can own, so they are ideal in a community tank with other passive tiny fish like platies, pygmy corydoras, neon tetras, and harlequin rasboras.
This small freshwater fish can tolerate a wide range of water parameters, but they do better in nano tanks with a temperature of 74° to 82°F, pH between 6.8 and 7.8, and a water hardness between 8 to 12 dGH.
Feed these freshwater nano fish a variety of freeze-dried, live, and frozen foods like brine shrimp, bloodworms, fish flake food, and the occasional vegetable.
NOTE
Bear in mind that guppies can breed very quickly, so you may end up with a lot of pregnant guppies if you keep males and females together. If you’d rather avoid being overrun with baby guppies, ask your local fish store for males only or sex them yourself. Males tend to be smaller, brighter, and have longer tails.
Specs
- Size: 1.5 inches
- Care Difficulty: Easy
- Required Tank Size: 10 gallons
If you’ve ever dreamed of owning an eel but don’t have the space or budget for one, the kuhli loach is your next best choice as they are much smaller (eels can grow between 1 foot to 6 feet long!) and take up less space.These freshwater fish have worm-like bodies but peaceful temperaments.
Kuhli Loach
The next aquatic species I recommend for a nano fish tank is the kuhli loach, a strange but unique fish that resembles an eel. They have long, slender bodies with very few scales, as well as large mouths surrounded by tiny barbels.
Reaching around 3 to 5 inches in length, a minimum tank size for this bottom-dweller is 20 gallons.
Tank Requirements
Kuhli loaches usually have black and yellow bands, but there are other color forms available, including black and white, reddish brown, and silver. These unusual fish are extremely shy, so they require a lot of aquatic plants, floating plants, driftwood, and caves in their tank to feel safe.
That being said, they are peaceful creatures that can be housed in a community tank with non-aggressive tank mates like ember tetras, corydoras, guppies, and platies.
While not schooling fish, kuhli loaches do better in groups of at least 5 to feel comfortable. They are mostly carnivorous, so offer them meaty foods like bloodworms, mosquito larvae, brine shrimp, and sinking pellets.
Specs
- Size: 3 to 5 inches
- Care Difficulty: Easy
- Required Tank Size: 20 gallons
Dwarf gouramis are stunning centerpiece fish that have intense orange-red and blue coloration. They are peaceful and have a lot of personality for such a little fish.
Dwarf Gourami
If you’re looking for a freshwater fish that will stop you in your tracks with its beauty, the dwarf gourami will do just that! This labyrinth species has a shimmery sheen to its body, complemented by orange-red and blue stripes that continue to their fins.
Females are less colorful with silvery-gray bodies and light yellow vertical stripes. Most specimens reach between 3.5 to 4.5 inches in length, so they are suitable in smaller tanks of at least 10 gallons.
Tank Requirements
Densely planted tanks with lots of floating live plants are ideal for dwarf gouramis. They can live alone, in pairs, or in small groups, but males can be aggressive towards one another. They can also be housed in community tanks with other peaceful fish.
Personally, my dwarf gourami’s tank mates include a small school of ember tetras that happily swim together and a few Japanese trapdoor snails.
This aquarium fish is omnivorous, so you can offer them a combination of meat-based and algae-based foods – they particularly enjoy bloodworms, mosquito larvae, and veggies like peas and zucchini.
Specs
- Care Difficulty: Easy
- Size: 3.5 to 4.5 inches
- Required Tank Size: 10 gallons
If you’d like a mini fish that can fit in a 10-gallon nano tank, the platy is the perfect solution. These charming fish are small but docile and colorful.
Platy
One of my all-time favorite fish for nano tanks is the platy, a peaceful but curious species that comes in a vast assortment of colors and patterns. They somewhat resemble goldfish in appearance, just a lot smaller (and less fish waste)!
They only grow to around 2 inches in length, with females usually being a bit larger.
Compatibility
Although not a shoaling fish, platies are happier when housed in at least a trio. However, like guppies, they are known for being prolific breeders. If you want to avoid your tank becoming overpopulated, consider keeping just males.
You can house them with other passive tank mates or in a separate species aquarium if you want them to breed without the fry being eaten.
Platies are omnivores and can be fed vegetables, fish flakes/pellets, and live or frozen foods.
Specs
- Size: 2 inches
- Care Difficulty: Easy
- Required Tank Size: 10 gallons
Harlequin rasboras are a small but attractive species with a coppery color and black markings. They are very passive, making them a fantastic option for all freshwater community setups.
Harlequin Rasbora
Boasting a glistening copper body adorned by a black porkchop-shaped marking, the harlequin rasbora is a pretty little fish for nano freshwater aquariums. They reach about 2 inches in length, so a minimum tank size for a small group is 10 gallons.
That being said, harlequins are a shoaling species, so it’s better to keep at least 6 of them. For a group this size, I’d suggest at least a 15-gallon planted tank as they are quite active species that like to explore.
Compatibility
Highly docile, the harlequin rasbora is a great option for community tanks – in fact, they are one of the few fish that can be housed with bettas. So, if you’d like a roommate for a betta fish, the harlequin rasbora is hands down the best choice!
Although classed as omnivores, harlequin rasboras prefer live food like bloodworms, daphnia, and brine shrimp. They can also be given high-quality fish pellets or frozen foods.
Specs
- Size: 2 inches
- Care Difficulty: Easy
- Required Tank Size: 10 gallons
Honey gouramis are quiet, gentle fish with either bright colors of red, orange, and yellow. They are one of the smallest species in the gourami family, reaching around 2 inches in size.
Honey Gourami
With their calm nature and small size (2 inches), the Honey Gourami is the perfect addition to a minimum tank size of 10 gallons, both in species-only and community setups. Males have much more intense coloration than females, and can be found in either yellow, orange, or red.
Compatibility
Females tend to be silver, brown, or gray, and are normally a little larger. These fish can be kept alone, in pairs, or in small groups, though males can be territorial towards one another, especially during spawning.
As mentioned above, males are much brighter once mature, so sexing this species is quite easy. Make sure your tank has lots of live plants, particularly floating species, and only house them with other passive tank mates.
Honey gouramis are omnivores, so feed them a mixture of algae-based and meaty foods. Bloodworms, tubiflex, fish flakes, algae wafers, and vegetables like spinach and zucchini are a few good feeding choices for this fish.
Specs
- Size: 2 inches
- Care Difficulty: Easy
- Required Tank Size: 10 gallons
If you’re looking for a pretty coldwater fish for a minimum tank size of 10 gallons, the zebra danio is the ultimate choice. This small fish has vivid blue stripes, a non-aggressive temperament, and is fairly hardy.
Zebra Danio
Next up is the zebra danio, a compact but lively fish with a lot of color. Growing to approximately 2 inches in length, these fish have silvery bodies with blue horizontal stripes.
They are a shoaling species, so aim to keep at least 6. While several can be housed in a 10-gallon nano tank, I’d advise a minimum of 20 gallons for a school of 6 as danios are very energetic.
Compatibility
These fish are docile and can be housed with other coldwater species like the white cloud mountain minnow, weather loach, hillstream loach, and rosy barb.
In their natural habitat, zebra danios consume a mixture of algae, mosquito larvae, worms, and small crustaceans, so try to replicate this in your nano aquarium.
Zebra danios are fairly easy to care for as long as you keep their tank in the following parameters: pH between 6.8 to 8, temperature around 64 to 77°F, and water hardness around 5 to 19dGH.
Specs
- Size: 2 inches
- Care Difficulty: Easy
- Required Tank Size: 10 gallons
With their friendly appearance, charming personality, and easy care, the Indian dwarf puffer fish has stolen the heart of many aquarists. They’re a fantastic option for nano tanks as they only grow to a maximum of 1.5 inches.
Indian Dwarf Puffer Fish
The last aquarium fish I recommend for a nano tank is the adorable Indian dwarf puffer fish, also known as the pea, pygmy, bumblebee, or malabar puffer. They only grow to a maximum size of 1.5 inches and have a golden-brown body with dark spots.
As such, the minimum tank size for this fish is 10 gallons. If you’d like to keep more than one, add between 3 to 5 gallons per additional puffer. This species can get territorial as they mature, so a larger tank is better.
The Indian dwarf puffer is one of my favorite freshwater species as they are curious, playful, and fascinating to watch, despite their very small size.
Compatibility
Unfortunately, this species can be aggressive with other freshwater nano fish, so they don’t usually do well in community tanks. While some aquarists have been successful in housing them with different species, I wouldn’t recommend it unless you’re an experienced fishkeeper.
They are carnivorous, so make sure you’re feeding them high-quality fish pellets, as well as live or frozen food like daphnia, baby brine shrimp, blackworms, and aquatic snails.
Good water parameters for pea puffers are: 7 to 8 pH, 74° to 82 °F, and 4 to 10 dGH.
Specs
- Size: 1.5 inches
- Care Difficulty: Easy
- Required Tank Size: 10 gallons
What Is a Nano Fish?
Nano fish are small species of fish that can be housed in tanks less than 30 gallons in volume.
What Is a Nano Fish Tank?
A nano tank is an aquarium that is smaller than 30 gallons, though most nano tanks are less than 10 gallons in volume.
What Is the Best Fish for a Nano Tank?
The best fish for a nano tank are small species that produce little fish waste and can thrive in a compact setting. Some of these fish include bettas, ember tetras, guppies, Indian dwarf puffers, as well as aquatic snails and dwarf shrimp.
How Long Do Small Fish Live For?
The average lifespan of small fish varies from species to species – some tiny fish like the guppy and betta only live for 2 to 3 years, whereas others such as the harlequin rasbora have a life expectancy of between 5 to 8 years.
Good water quality, a varied diet, and stable water parameters are key to keeping aquarium fish healthy and long lived. Also, if you just got your new fish, don’t ever forget to acclimate the fish to prevent shock and health issues.
How Many Fish Can You Keep In a 10-Gallon Tank?
TIP
Many aquarists use the “1 inch of fish per gallon of water” rule to help them stock their aquariums. But this general rule doesn’t work for all species, so make sure to research the fish you’re planning to keep properly before buying them.
Feel Free To Share!
I hope I helped you select the best nano fish for your small tank. It’s always best to understock your tank as overcrowding can lead to poor water quality and fluctuations in water parameters, which can contribute to stress and ill health in fish. These causes of stress if not addressed might lead to diseases or even death.
Which small fish caught your attention? What did you end up choosing for your aquarium? Be sure to let me know on our social media platforms (I’d love to see some photos of your setup!), and share this post with your friends and family – they might be encouraged to start a nano tank of their own.
