Fish For A Small Aquarium | A List of the Best Freshwater Fish

Last updated on December 24th, 2022 at 11:05 am

Most people are in search of fish for a small aquarium. Those who dream of the first aquarium in their life usually imagine a 20–25-liter tank. For beginners, it seems that this is the optimal size in which you can easily create your own underwater world. There are those people who, for some reason, really can’t get a large aquarium at home. 

Fish For A Small Aquarium

Sometimes unpretentious aquarium fish is vital. And there are also aquarists whose goal is to maintain a nano aquarium with small fish. All this is quite real. In pet shops, you can find aquariums for beginners, and unpretentious fish for a small aquarium, and even special devices for creating a truly correct biotope.

Small Home Aquarium: Terms & Conditions

Even small fish require attention and respect. It is more difficult to create good conditions in a 10-liter tank than in a 100-liter tank. Useful information for a beginner – basic requirements for a home aquarium:

  • Pure water. There should be no objects in the water that release harmful substances into the water.
  • Compliance with parameters. Even the smallest aquarium fish cannot live in very alkaline or overly acidic environments, high in chlorine or nitrates. Stiffness, acidity – all this will have to be checked regularly.
  • Compliance with the requirements of the fish. If the fish needs soil at the bottom, it should be there. If the fish does not need aeration, then the beginner is lucky and there is no need to install a compressor.
  • At least minimal maintenance. Like any animal, fish for a small aquarium will still require attention from you: for example, regular water changes.
  • It is especially difficult to maintain the temperature in small aquariums. You will have to carefully monitor the temperature of the water.
  • It is equally important to ensure that there is no overpopulation in the nano aquarium. Compatibility is the most important parameter when choosing.

Pros Of Small Aquariums

You can place the small tank on any level surface: the water pressure is not strong enough to create problems. In the nano container, you can create a unique design that will fascinate every viewer. The small aquarium is easy to rearrange, and there is no difficulty with moving.

Choosing Fish For A Nano Aquarium

Small aquarium fish are sold at every pet store that sells animals. The vast majority of residents of small tanks are unpretentious freshwater fish. They can be very beautiful despite their micro size.

It is rare that different fish are kept in small aquariums, usually, these are monospecific reservoirs, containing a maximum of 5-10 inhabitants. However, it all depends on the volume.

Small Fish For An Aquarium : Top 10 Popular Species

  • Sumatran barbs. Live, mobile fish that need a strong current. Therefore, when setting up an aquarium, it is important not to forget about the filter that this flow will create. Good conditions – an aquarium from 30 liters per flock. It is better if the aquarium is larger. Barbs do better in cool water, which is very difficult to organize in mini aquariums.
small aquarium fish
  • Somik corridor (speckled). Small, unpretentious fish that live mainly on the bottom. They do not need additional air, since they have “intestinal breathing” and they breathe not only with gills. Peaceful, calm, and positive fish that will become good neighbors to other representatives in an aquarium with a volume of 30 liters or more.
Somik corridor
  • Poecilia is quite tolerant of the bad conditions of creation. Unlike colored fish, guppies have a restrained range and a somewhat combative disposition. Easily fit into aquariums from 30 liters, but prefer larger tanks. Overpopulation can start a war. Often in small aquariums, they coexist with small catfish.

Related : Start Your First Fish Tank, But How? | Beginner’s Guide

More Small Aquarium Fish

  • Lemon tetra. Grows up to 4 cm, loves a flock of self-like. Undemanding to conditions and easy to care for and maintain. Bright, and with the right lighting it becomes irresistible.
Lemon tetra.
  • Dwarf Gourami: They belong to the labyrinth, which means they have a special breathing system that allows you to do without aeration. For small aquariums this is very important as it can be very difficult to mix a 20–30-liter compressor.
  • Guppy. Perhaps the most popular fish, which is known not only by beginners, but also, in principle, by people far from aquarists. Male guppies are bright, with lush fins. Females are larger, but less attractive. Guppies are peaceful and viviparous; under good conditions they can reproduce spontaneously. The optimal volume is at least 20 liters for 5-6 fish. They have a livable character, but in a close team they can become nondescript and often get sick.

An interesting fact: despite the fact that it is customary for us to treat guppies lightly, there are real connoisseurs of this species. They strive to get rare and unique breeds; they spend a lot of money on them.

  • Cardinal. Like guppies, male cardinals are brighter than females, but in principle, fish of both sexes look good in a small aquarium. They need a flock of self-like ones – at least 12-15 pieces. Calm and cheerful fish that breed successfully under the right conditions. An aquarium for such a flock should be from 40 liters.
  • Iriaterina Werner. Fish up to 6 cm in size, with large beautiful fins. Requires an aquarium from 30 liters for 2-3 pieces. Extremely demanding on water parameters.
  • Notobranchius Rakhova. The males of these fish are incredibly bright, orange-blue. For one family of 2 fish, a capacity of 20-25 liters is enough. But they are demanding on parameters and temperature (they prefer cool water).

Fish For Nano Aquariums

Nano aquariums include tanks of 4 liters, 5 liters, and up to 10 liters. By themselves, such home aquariums are very convenient: they become a decoration of the desktop along with family photos and stationery. But in order for the fish to live happily ever after in them, you need to take special care of the micro aquarium.

  • Cockerels. It is believed that this bright fish with lush fins and amazingly beautiful colors can live in a glass of water. Of course, this is a delusion, one individual should have at least 4-5 liters, and optimally – 7-10 liters. If you want the fish to be happy, the male cockerel needs an aquarium of 30 liters and 2-3 females. Two males will definitely not get along in a mini aquarium.
  • Neon. One of the smallest fish for an aquarium. Theoretically, several individuals will do well even in a volume of 10 liters. But neon’s can hardly be called unpretentious. They prefer to live in flocks of 10-15 pieces, and for such a quantity, a reservoir of at least 40 liters is needed. In addition, neon’s, like striped zebrafish, are demanding on water parameters. Neon’s rarely get along with other fish – they are defenseless.
  • Danio. Similar in size and behavior to neon’s, but do not need a large flock. Appearance – longitudinal dark stripes on a light background. There are also spotted and red. They have a wide range of temperatures (from 15 to 30 degrees), but like all living settlers of aquariums, they do not tolerate sudden changes.

More Fish For Nano Aquariums

  • Micro-collection. Perhaps the most unpretentious aquarium fish for a small aquarium grow up to 2 cm. Only 1 liter of water is required per individual, so a mini-flock can be comfortably placed in a nano aquarium. They look especially good in aquariums filled with live plants and mosses (aquascape); this is done by professionals in nano-aquarists. But a beginner looking to master aqua scaping can start with a small tank.
  • Norman’s blue eyes. If you organize the right lighting, the fish will play with amazing neon shades: this is how the eyes of small fish will glow. The size of each individual is 3-4 cm. Playful, active; they are successfully placed in aquariums of 15-20 liters.
Norman's blue eyes
  • Dwarf tetra don. A rare fish so far, bred specifically for small containers. For a couple of fish, 10-15 liters are enough. But tetra don is a rather aggressive fish that can start a war for territory, therefore, if possible, it is better to find a larger container and equip it correctly.
Dwarf tetradon
  • Tetra Amanda. Several fish 2 cm long can live in a tiny aquarium, however, tetra is a schooling fish, so the best option is a tank of 30-40 liters and a flock of 6 pieces. They require good filtration: the water must be clean.
Tetra amanda
  • Neoheterandria elegance. While a little-known breed, it has a bright brindle color and unpretentious character. For a couple of fish 2.5-3 cm in size, 10 liters of water is enough. Good fish for beginners, there is one drawback: while they are difficult to find on sale.
Neogeterandria e

How To Get a Fish And How To Combine Them In Small Volumes

Aquarium 4-5 liters: it is better to leave without live fish, you can be limited to just a beautiful design.

Aquarium with 10 Liters Of Water

  • 1 cockerel
  • 3-4 cardinals
  • 4-5 guppies or Endler’s guppies (these are natural individuals; they are even smaller than the ones we are used to breeding by breeders)
  • 4-5 neon’s
  • 4-5 blue eyes of Norman
  • up to 10 micro-collection.

In such a tank, it is better not to combine several species: the flocks will turn out to be too small, and the fish will not live happily.

Aquarium With 20 Liters Of Water

  • 1 male cockerel with 2-3 females
  • 12-15 guppies
  • up to 20 zebrafish or neon’s
  • 5-7 cardinals
  • 10-12 happy neon’s
  • up to 20 micro-collection.

You can combine

  • 5 guppies and 5 zebrafish
  • 10 guppies and 2 speckled catfish
  • 7-8 neons and 2 speckled catfish.

Aquarium For 30 Liters Of Water

  • 4-5 barbs
  • 2-3 Apistogramma
  • 12-15 cardinals
  • 20-25 neon’s or zebrafish
  • 2-3 macropods
  • 2-3 iriatherina werneri
  • 10 parsing.

30-40 liters is considered ideal for a beginner. It is convenient to observe the behavior of fish, track diseases and organize feeding.

How Many Fish Live In Small Aquariums?

A hot question, especially for beginners. Small fish rarely live up to the age of 2 years. It is enough to open and read the description of any small fish. It indicates the maximum life span in captivity, with proper nutrition, no stress, and good care. If the conditions are not suitable, the fish live even less. Their condition is negatively affected by:

  • Dirty water
  • Overpopulation
  • Wrong food
  • Lack of vital objects (shelter, live plants, soil, aeration, filter)
  • Constant stress
  • Incorrect temperature conditions
  • Infections brought in with dirty equipment or new fish. If someone gets sick in a small aquarium, the infection is likely to spread to all inhabitants, including catfish.


The smaller the aquarium, the less suitable it is for keeping living things. Therefore, a Nano aquarium is considered a challenging endeavor. However, small home aquariums of 30 liters are quite suitable for beginners: you can place a lot of unpretentious fish in them, beautifully arrange and supply them with a filter and a compressor. Do not forget that even a small aquarium requires regular maintenance: cleaning the soil, walls, water changes.

4 thoughts on “Fish For A Small Aquarium | A List of the Best Freshwater Fish”

  1. We’re a group of volunteers and opening a new scheme in our community. Your site offered us with valuable info to work on. You’ve done a formidable job and our entire community will be thankful to you.


Leave a Comment