Top 10 Stunning Nano Fish for your Next Small Fish Tank


Top 10 Stunning Nano Fish for Your Next Small Fish Tank

Nano fish tanks are very popular for their beauty and compact size, but it can be challenging to find animals that are tiny enough to comfortably live in them. If you only have room for a 5- to 20-gallon aquarium, check out our top 10 small aquarium fish that are known for their vibrant colors, fun personalities, and unique appearances.

1. Celestial Pearl Danio

Danio margaritatus

The CPD (or galaxy rasbora) is a name for this tiny fish that has been very popular ever since it was discovered in 2006. This tiny fish is originally from Southeast Asia and measures just 1 inch (2.5 cm). It’s covered in bright orange fins and shiny golden spots. They are a bit more expensive at $6-10 each so save your money and get at least six schooling fish. CPDs are known to be a bit shy, so make them feel safer by increasing the size of their group and providing plenty of decorations and aquarium plants as cover. Plus, they prefer feeding midwater (not at the top or bottom of the tank), so look for small, slowly sinking foods such as frozen cyclops, baby brine shrimp, and daphnia.

2. Chili Rasbora

Boraras brigittae

Chili rasboras get their common name from the fiery red color they display as full-grown adults, but most of time you see juveniles at the fish store that are much paler in appearance. If you bring them home and take good care of them, your patience will be rewarded when their coloration blossoms six months down the road. As one of the smallest fish on our list, they grow up to 0.8 inch (2 cm) in length with a very slender profile. Because of their petite size, they look better if you get at least 10 brigittae rasboras in a school and put them against a lush green background of plants. As with the celestial pearl danios, feed them tiny foods that swirl midwater in the aquarium, such as baby brine shrimp, crushed flakes, and Easy Fry and Small Fish Food.


3. Pygmy Corydoras

Corydoras pygmaeus

They are about the same size as baby cory catfish, and they can be just 1 inch (2.5 cm) long. Because they have whisker-like barbels, they can detect and pick up any crumbs on the ground. They will eat almost any type of fish food, including Repashy gel foods and sinking wafers. Pygmy corys, a schooling fish, require at least six fish to feel comfortable. However, if they are difficult to find in fish shops, you might consider other dwarf corydoras species like C. habrosus or C. hastatus. See our care guide for more information about cory catfish care.

4. Kuhli Loach

Pangio kuhlii

Although this bottom dweller can grow up to 4 in (10 cm) in size, it is not a micro fish. However, their slim, eel-like bodies mean that they don’t produce much bioload. These oddball creatures are great to keep with your other nanofish due to their unusual appearance and peaceful demeanor. Kuhli loaches are a great beginner fish since they are not picky when it comes to water parameters and food preferences. You can also check out the silver kuhli loaf (P. anguillaris) for additional color options. All details can be found in the care guide.

5. Green Neon Tetra

Paracheirodon simulans

Paracheirodon simulans is a smaller cousin to the neon tetra. It measures approximately 1-1.25 inches (22.5-3 cm) in length and has a very thin red stripe. Instead, the body is covered with a bright blue-green horizontal stripe. This makes it shine brilliantly even in dim light. Although they can survive in more acidic water, they will thrive in tropical community tanks that have the same water parameters. A school of 6-8 neon tetras is recommended. They should be fed small, slow sinking fish foods. Also, many of them are caught from the wild and may come with fin rot or ich, so make sure to quarantine them after purchase to prevent disease from spreading to your other aquariums.

6. Clown Killifish

Epiplatys annulatus (male is above and female is below)

The banded panchax or rocket killifish is known for its dark vertical bands and dazzling tail that looks the flame coming out of a rocket. All the incredible colors are found in the males, while the females are covered with a transparent tail and have a banded physique. Because the guys can be a bit territorial with each other, aim for a group with a ratio of 1 male for every 2-3 females. This 1.5-inch (3.8 cm), top-dwelling fish prefers to hang out in the upper third of the aquarium, so use a tight-fitting lid with all the holes plugged up so that they won’t jump out. You can give them floating foods like freeze-dried tubifexworms and flakes and they will begin spawning and scattering eggs. For more details, read our article on clown killies.

7. Ember Tetra

Hyphessobrycon amandae

This 0.8-inch (2 cm) tetra from Brazil boasts a bright orange-red body that lights up any aquarium, especially those with lush, green plants. They can be kept in both a small tank or as a group of 20-30 fish in larger tanks. Unlike many nano fish, ember tetras are relatively outgoing and eagerly eat from all levels of the aquarium. Feast them with floating or slowly sinking foods such as Hikari Micro Pellets, Xtreme Nano Pellets, and frozen Daphnia.

8. Panda Guppy

Poecilia reticulata

Last but not least, we have a livingbearer (or fish which bears young). Guppies are very well-known in the hobby, but they usually grow up to 2.5 inches (6 cm) long. Panda guppies were specifically bred for a small size and shorter tail. Females can reach around 1 in (2.5 cm), while males can reach 1.75-2 in (4-5 cm). They are a striking combination of black, silver, and blue colors.

We don’t think they are fussy, unlike other fancy guppies. In fact, we have raised them in an outside mini pond during the warm summer season. If you have water that is soft, Wonder Shells or Seachem Equrium may be an option. Fortunately, they are easy to feed and readily eat at all levels of the aquarium, so you don’t need to get a bottom dweller to clean up your nano tank. Panda guppies are one of our favorite varieties, so make sure to give them a shot. See our full guppy care guide for more details.

9. Spotted Blue Eye Rainbowfish

Pseudomugil gertrudae

If you have always loved rainbowfish but don’t have a tank big enough for them, try Pseudomugil rainbowfish like Gertrude’s rainbowfish. This lovely, 1.5-inch (3.5 cm) species has a yellow or light blue body (depending on its native region), black spots, and bright blue eyes. Although the males are brighter than the females (depending on their native region), you can get one male to every two females. This will ensure that the boys show off the best colors and perform unique sparring moves. Similar to the guppies they prefer higher pH and GH. However, they can survive in a wide temperature range.

As a surface-dwelling fish that likes to swim in the top half of the aquarium, get a tight-fitting lid to prevent jumping and feed lots of floating foods like flakes and freeze-dried foods. Although Pseudomugil Rainbowfish are vibrant and beautiful, their lifespan is shorter. Therefore, you might consider breeding them with dense floating plants such as guppy grass or yarn spawning mop.

10. Borneo Sucker Loach

Gastromyzon sp.

We also have an algae eater to help you keep your nano fish tank healthy. The Gastromyzon genus consists of hillstream loaches that usually stay 2 inches (5 cm) in length and are shaped like miniature stingrays or flounders. Similar to their bigger cousin, the reticulated Hillstream Loach, they love eating algae and cleaning out driftwood. They can be kept in normal community tank parameters, but also have the ability to tolerate the cooler temperatures of an unheated aquarium. Borneo sucker loaches can be territorial and may act in a way that is not normal for their species. You can get one individual or a whole group.

You can order these fish online if you’re unable to locate them at your local fish market. All the best with your nano-tank and have fun in nature.