Top 10 Stunning Nano Fish for your Next Small Fish Tank

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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. It is a miniature trout that was originally from Southeast Asia. It has shiny golden spots and bright orange tails. They can be a little pricier at $6-10 each, so save up your money to get at least six of these 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

The name Chili rasboras comes from their fiery red coloring as adults. However, you will often see juveniles in the fish shop that are paler. Your patience will pay off when they turn a vibrant color six months later if you bring them home. They are the smallest of our fish and can grow to approximately 0.8 inches (2 cm) in size. Their profile is very slim. 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 love to eat any kind of fish food, even Repashy gel food and sinking wafers. Pygmy corys are a schooling fish that require at least six or more to feel comfortable, but if you’re having trouble locating them at fish stores, consider the other dwarf corydoras species, like C. habrosus and C. hastatus. Our care guide provides more information on caring for cory catfish.

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 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. You can read all about them in the full care guide here.

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. 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. Due to the fact that males can be territorial, you should aim for a group of at least one male per 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. Feast them with floating or slowly sinking foods such as Hikari Micro Pellets, Xtreme Nano Pellets, and frozen Daphnia.


8. Panda Guppy

Poecilia reticulata

We also have a livebearer, or fish that bears young, on our list. Guppies are well-known in the hobby. They can grow to 2.5 inches (6cm) in length. 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 have striking blue, silver, and black colors and, like most livebearers, breed quite readily.

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 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 a favorite variety, so be sure to give them another chance. 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. 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. While the males are more colorful than the females, get one male for every two females so that the boys will show off their best colors and 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. Pseudomugil rainbowfish can be very vibrant and beautiful but they have a shorter life expectancy. To breed them, use dense floating plants like guppygrass or spawning mops made of yarn.

10. Borneo Sucker Loach

Gastromyzon sp.

Last but not least, we have an algae eater for your nano fish tank. Gastromyzon genus is made up of small hillstream loaches, which are typically 2 inches (5cm) long. These loaches look like miniature stingrays and 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.

If you are unable to find these fish at your local fish store, check out our favorite online retailers to see about ordering them online. Best of luck with your nano tank and enjoy nature daily.