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 attractive due to their small size. However, it can prove difficult to find tiny animals that will 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

This little fish is also known as the CPD or galaxy rasbora. It has been very popular since its discovery 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. These schooling fish can be quite expensive at $6-10 per piece, so make sure you save enough money to buy at least six. 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. They prefer to eat midwater, which is not at the top or bottom of their tank. Therefore, you should look for slow sinking foods like baby brine shrimps, frozen cyclops 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. They look best when there are at least 10 brigittae rasasboras and they are placed in a school with a backdrop of lush green 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

Because they are only 1 in (22.5 cm) tall, pygmy corydoras can be as cute as baby cory cats. They are a good pair with previous schooling fish, as they can use their whisker-like barels to pick up any crumbs and clean them up. They enjoy eating just about any fish food, including sinking wafers and Repashy gel food. Pygmy Corys are schooling fish and require six or more fish to feel at ease. If you have trouble finding them in fish stores, try the dwarf corydoras species C. habrosus, 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. They are a great oddball fish to keep with other nano fish due to their peaceful disposition and unusual appearance. Because they don’t have a preference for food or water parameters, kuhli loaches make a great starter fish. 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. Its body is covered in a bright, blue-green horizontal stripe, which shines brilliantly even at night. They can live in slightly more acidic water, but otherwise thrive in standard water parameters for a tropical community tank. Get a school of at least 6-8 green neon tetras and feed them plenty of small, slowly 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 or banded panax is famous for its dark vertical stripes and brilliant tail. This tail looks like a flame coming out of an explosion. The males have all the amazing colors, whereas the females have the banded body with a clear tail. 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. Our article on clowns is full of more information.

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. You can feed them floating or sinking food like Hikari Micro Pellets and frozen daphnia.

8. Panda Guppy

Poecilia reticulata

We also have a livebearer, or fish that bears young, on our list. Guppies are a well-known breed, and can grow to as much as 2.5 inches (6 cm) in length. Panda guppies have a smaller size and a shorter tail. Males are approximately 1 inch (2.5cm) in length, while females are about 1.75-2cm (4-5cm). These guppies are striking in their blue, silver and black colors. They also breed very easily, just like other livebearers.

Compared to other fancy guppies, we don’t find them to be very fussy and have even raised them in an outdoor mini pond during the warmer summer season. 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. For more information, see our complete guppy care guide.

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. 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. They prefer higher pH and GH but can survive in a wide range of temperatures, just like the guppies.

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. Gastromyzon is a genus of hillstream loaches. They are usually 2 inches (5 cm) long and shaped like tiny stingrays or flounders. Like their larger cousin, the reticulated hillstream loach, they enjoy cleaning off driftwood, scavenging for leftovers, and of course eating algae. 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.

These fish are not available at your local fish shop. We recommend you check out these online retailers. Best of luck with your nano tank and enjoy nature daily.