Best Small Fish for Freshwater Nano Tank

If you have very limited space and/or budget, then you probably have decided than a nano fish tank is the best choice for you to get into fish keeping hobby. That is why we have put together this informational guide about some of the best small fish for nano tanks, so you can find the perfect inhabitants in your little ecosystem.

If this is going to be your “first rodeo” in fish keeping, we suggest you read our article about common fish keeping mistakes so you are well prepared for this great hobby.

And, if you still haven’t decided on what kind of aquarium you should get, we have a list of reviewed and inspected tanks right here - Best Small Nano Fish Tanks.

Just remember that it much easier to start with a larger fish tank. Nano aquariums will require more attention and will be less forgiving, when you make a mistake. That is due to the total capacity of water, which means, smaller amounts can get contaminated much faster. Smallest nano tank we can recommend has to be atleast 5 gallons, otherwise your fish will be very restrained. Overall, we suggest getting a tank that is atleast 8 gallons. So let’s help you find which ones are the best nano fish for your aquarium.

Siamese Fighting Fish - Betta Splendens

White Siamese Fighting Fish

Siamese Fighting Fish comes from Southeast Asia, Thailand and Cambodia and belongs to the family of gourami, which are foam nest builders and grow to a length of 2-3 inches in about 3 years. The males are more colorful than the females, who have much shorter fins. They should be used in pairs or a single male with several females together, because the males are very aggressive with each other.

  • Maximum number of fish in an 8 gallon nano tank: 4
  • Temperatures: 75 to 80 °F (24 to 26°C)

The Mosquito Rasbora - Boraras brigittae

Red Mosquito Rasbora

The mosquito rasbora is native to the Indonesian part of Kalimantan and can live for up to 7 years with a size of approx. 1 inch. Rasboras love a dense vegetation, which allows them a retreat from all the stress. Like all Rasboras, it is a schooling fish and should be placed together with 7-10 fish of its genus.

The upper shining orange-red longitudinal line is supplemented by a shining orange-red line in the lower range. In order to fully enhance the luminosity of this small fish, the bottom should be kept dark and the water surface covered with floating plants.

  • Temperatures: 70 to 75 °F (22 to 24°C)
  • Maximum number of fish in an 8 gallon nano tank: 10

Asian Stone Catfish - Hara jerdoni

Asian Stone Catfish

This asian catfish is resident in Bangladesh, India or Nepal and has a size of approx. 1 - 1.5 inches. It is very peaceful during night time and spends most of the day just lying at the bottom. It lives in a water with some current and enjoys roots or stones as cover. It is a very friendly fish and can live together with basically any other fish.

  • Temperature: 65 to 72 °F (18 to 22°C)
  • Maximum number of fish in an 8 gallon nano tank: 10

Dwarf Gourami - Colisa lalia

Dwarf Gourami

The dwarf gourami lives in the delta area of the large rivers of the Indus, Ganges and Brahmaputra, where they live in large swarms. In the aquarium, the dwarf gourami is kept wisely by couples and loves dense planting. However, since it belongs to the labyrinth fish species, it needs a small free area at the water surface to catch air. Emerald green horizontal stripes, on a strong red body, make the dwarf gourami a coveted specimen for the nano aquarium.

  • Temperature: 71 to 75 °F (22 to 26°C)
  • Maximum number of fish in an 8 gallon nano tank: 2

Glowlight Tetra - Hemigrammus erythrozonus

Glowlight Tetra Fish

The glowlight tetra is native to the river basin of the Essequibo River in Guyana and is an unmistakable nano fish due to its distinctive colouring. Bright orange-red stripes that extend from the tip of the mouth to the caudal fin. The glowlight tetra is a schooling fish and should be placed together with 6-8 fish, which also love the lower water zones. Its bright color is most noticeable for this 1.5 inch fish when the ground is dark and the water surface is densely overgrown.

  • Temperature: 73 to 77 °F (23 to 25°C)
  • Maximum number of fish in an 8 gallon nano tank: 15

Neon Green Rasbora - Microdevario kubotai

Nano Neon Green Rasbora

The neon green rasbora is also known as the emerald dwarf rasbora due to its shimmering green color and comes from Myanmar. Due to its size of only about 0.7 inches and the beautiful coloration, it is one of the rarities among the nano fish. It loves the company with other animals, but may only be used with small fish species otherwise they will get eaten. This fish is perfect for planted tanks.

  • Temperature: 71 to 77 °F (22 to 25°C)
  • Maximum number of fish in an 8 gallon nano tank: 12

Ember Tetra - Hyphessobrycon amandae

Ember Green Tetra

Ember tetras come from Brazil, the Mato Grosso region. It is a schooling fish and must be placed together with 6-10 animals. With its size of 0.7 to 1.2 inches the tetra belongs to the small fish species that are very well suited for nano fish tanks. A dense planting of the tank offers them the ideal retreat possibility. If the ember tetra is held in well filtered water, its red coloring shows off more intensively and more beautifully.

  • Temperature: 71 to 75 °F (22 to 24°C)
  • Maximum number of fish in an 8 gallon nano tank: 12

Celestial Pearl Danio - Danio margaritatus

Celestial Pearl Danio Fish

Home of the celestial pearl danios is Myanmar (Burma) and northern Thailand and they dwell in plant-rich waters. With the average size of just under an inch, it belongs to the smaller ornamental fishes and can live up to 3 years. Its color variety, blue - white - orange with golden-yellow points, makes it a very sought-after fish. The males stand out with more powerful colors. The females are only slightly colored at the base of the fins. In the tank they love dense edge planting and must be placed in a school of 6-8 fish. Celestial Pearl Danios definitely look very beautiful in nano aquariums.

  • Temperatures: 65 to 71 °F (18 to 22°C)
  • Maximum number of fish in an 8 gallon nano tank: 10

Least Kilifish - Heterandria formosa

Least Kilifish

Least Kilifish is from the south of the USA, where they love strongly herbed waters. The least kilifish is one of the smallest live-bearing kilifish and usually live for about 3 years. The females are approx. 0.8 to 1.4 inches long and the males are only approx. 1 inch. These small nano fish must be placed in a schooling group, ideal would be 4 males and 6 females. The tank should be densely planted.

  • Temperature: 60 to 75 °F (16 to 24°C)
  • Maximum number of fish in an 8 gallon nano tank: 8

Neon tetra - Paracheirodon innesi

Nano Tank Neon Tetra

Neon tetras are found in clear water streams of the rainforest of Peru and in the upper reaches of the Amazon. The neon tetra is a typical schooling fish that must be kept in an aquarium with at least 15 fish of its species. The tank should have a dark bottom and a dense planting of tender ferns. Tree roots, branches and stones provide suitable cover for the lively but peaceful tetras. In darker aquarium settings the fluorescent colors of the neon tetra really come to life. Overall, neon tetras are not only one of the best fish for nano fish tanks, but they do well in larger setups together with other fish as well. They are very active and friendly small sized fish.

  • Temperature: 68 to 75 °F (20 to 24°C)
  • Maximum number of fish in an 8 gallon nano tank: 15

Hopefully, this article was a short intro that will put you on to the right path so you can find the perfect nano fish your small nano aquariums. Be sure to take a look around our website, because we have many articles about fish keeping that you will find useful and more detailed guides about taking care of specific fish species.

If you are interested in freshwater tropical fish, you can check out our Tropical Aquarium Fish List.