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

Although chili rasboras are known for their fiery red color as fully grown adults, most juveniles you see at the fish market are much paler. You will see a change in their coloration six months after they are born if you take care of them and bring them home. This fish is the smallest on our list and can grow up to 0.8 inches (2cm) in length. They have a very thin profile. Their small size makes them look great if there are at most 10 brigittae rose rasboras placed in a school. 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

The 1-inch (2.5 cm) pygmy corydoras are incredibly adorable because they always stay the size of baby cory catfish. They pair well with the previous schooling midwater fish because they can use their whisker-like barbels to detect and clean up any crumbs that fall past them to 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

This bottom dweller is not quite a micro fish since it can reach up to 4 inches (10 cm) in length, but they do not produce much bioload or waste because of their skinny, eel-like bodies. These oddball creatures are great to keep with your other nanofish due to their unusual appearance and peaceful demeanor. Kuhli loaches can be a great fish for beginners as they aren’t picky about water conditions or food preferences. You can also check out the silver kuhli loaf (P. anguillaris) for additional color options. The full care guide can be found here.

5. Green Neon Tetra

Paracheirodon simulans

As a slightly smaller cousin of the regular neon tetra, Paracheirodon simulans only gets 1-1.25 inches (2.5-3 cm) long and doesn’t have much of a red stripe. Its body is covered in a bright, blue-green horizontal stripe, which shines brilliantly even at night. Although they can survive in more acidic water, they will thrive in tropical community tanks that have the same water parameters. You should have at least six to eight green neon tetras in your tank. Give them 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 rocket killifish, also known as the banded panchax, is well-known for its distinctive dark vertical bands and stunning tail. It looks like a flame rising from a rocket. Males are able to display all the colors while the females have a banded body and a clear tail. The guys can get territorial so aim to have one 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. Offer them floating foods such as freeze-dried tubifex worms and flakes, and they should start spawning and scattering their 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. These tetras are extremely hardy and can be housed in a tiny tank or in a large tank with 20-30 fish. Unlike many nano fish, ember tetras are relatively outgoing and eagerly eat from all levels of the aquarium. Feed them floating or slowly sinking foods like Xtreme Nano pellets, Hikari Micro 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 are specifically bred to maintain a small size with a shorter tail, such that males come in around 1 inch (2.5 cm) and females around 1.75-2 inches (4-5 cm). They have striking blue, silver, and black colors and, like most livebearers, breed quite readily.

They are not fussy like other fancy guppies. We even have them raised in an outdoor mini-pond during the summer. If you have soft water, Wonder Shells and Seachem Equilibrium might be a good choice. They prefer a higher pH and GH with greater minerals. 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

Pseudomugil rainbowfish such as Gertrude’s Rainbowfish are a good choice if you’ve always loved rainbowfish and don’t have the space to keep them. The 1.5-inch (3.5 cm), beautiful species of rainbowfish has a bright blue eye, black spots and a light blue body. The males are more colorful than their female counterparts. Therefore, you should get one male for every two women. This will allow the boys to show off their best colors as well as their unique sparring dance. Like the guppies, they do prefer higher pH and GH, but can live in a very 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.

The last but not the least, we offer an algae eater for your nano tank. 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 show some territorial behavior toward their own kind, so either get one individual or a group of three or more.

These fish are not available at your local fish shop. We recommend you check out these online retailers. All the best with your nano-tank and have fun in nature.