What are nano aquariums?

Nano fish tanks are nothing more than aquariums with a small area of 30-40l. Usually, it is cube-shaped, although there are some cylindrical or spherical ones. In addition to their small dimensions, they are characterized by an extraordinary emphasis on aesthetics, and their goal is to achieve an effect that reflects the natural conditions as much as possible. The fashion for this type of aquarium came from Japan because the Japanese are famous for their love of carefully developed, miniature forms.

What can you grow in nano tanks?

Of course, a small litre capacity entails a lot of limitations in the choice of cast, because most living creatures, however, need space to live. The case is also not made easier by the most popular cube shape, in which active fish cannot “speed up”. However, there are species of fish and (especially) other living creatures that feel great in such tanks.


The planted nano aquarium is the safest version, and also allows for the best aesthetic effects. In an aquarium of very small sizes, small plants are recommended, for example:

-Marimo (Cladophora aegagropila)

-The jagged germanderwort (Riccardia chamedryfolia)

-Java fern (Microsorum pteropus)

-the floating crystalwort (Riccia fluitans)

-eared watermoss (Salvinia auriculata)

-pearl grass (Hemianthus micranthemoides)

-Blyxa japonica

-downoi (Pogostemon helferi)

-lucens (Cryptocoryne x willisii)

-Anubias nana

– Echinodorus tenellus

Echinodorus quadricostatus

As well as many other aquarium plants, the common feature of which is a small size and attractive appearance. A special type of nano plant aquarium is Wabi kusa, which is something like a small paludarium in which plants grow above the surface of the water but are limited by the walls of the vessel.


Shrimp tanks have been very popular for over a dozen years, and the shrimp themselves are the most frequently chosen creatures for nano aquariums. The so-called dwarf shrimp, up to a maximum length of 4 cm will be the best choice for such aquarium e.g.:

– Cardina Japonica

– Cardina cf. babaulti

– Cardina graciliostris

– Cardina cf. cantonensis

– Cardina cf. breviata

– Neocardinia heteropoda

Shrimps do well in “cube” aquariums, and even in various types of “jars”, ie tall tanks with a small bottom area. They are not problematic inbreeding, but they have quite high requirements in terms of water quality – it must be crystal clear and well aerated. Therefore, you need a good filter system and frequent water changes – preferably about 1/3 once a week. They mainly eat algae from the aquarium, sometimes it is necessary to feed them with special food for shrimps. They like tanks with lots of plants and not too intense lighting. They should not be kept in the same tank with fish.


Snails are a good choice for a nano aquarium for beginners and busy people: they feed practically on their own and do not have high water requirements.  Unfortunately, they often eat plants, thus destroying precise underwater landscaping. And without natural enemies, they breed very quickly.

Species with small sizes and decorative shells, such as:

– various species from the Ampullariidae family

– various species from the Planorbidae family, with particular emphasis on the Plonorbarius corneus sp. Pink and Anisus calculiformis

– Neritina (Neritina natalensis), an exotic snail that comes in several beautiful varieties: Zebra, Tiger, and Red Onion. Especially recommended because it does not eat plants

– Melanoides tuberculatus

– Brotia Pagodula

Snails mainly feed on algae and plant and animal debris, thus keeping the aquarium clean. Apart from the right temperature (when they are too cold, their life processes slow down), they do not have any special requirements for water. They can be bred together with small, non-predatory fish. The aquarium must have a tight lid.


Very rarely bred in traditional aquariums, and due to the low dynamics of life – treated rather as an element of decoration than an animal. In the case of a nano aquarium, the mussels can be properly displayed and thus become the main attraction of a small tank. The yellow clam (Corbicula javanicus), characterized by beautiful intense color, is especially recommended for the nano aquarium. The mussels eat food filtered from the water, in the case of very clean tanks they may starve – then they can be fed with liquid food for shrimps.


Despite the fact that hydra are just perfect creatures for a nano aquarium and, in addition, they are easy to obtain from natural water reservoirs – for unclear reasons, there has been no fashion for hydra breeding so far. Perhaps the reason is the low-intensity coloration or common occurrence of these creatures. Nevertheless, hydra in very small aquariums look very interesting, and if the tank is additionally equipped with a magnifying glass – it can be a very interesting object of observation. Hydras do well in almost any water and any shape of the reservoir. They require feeding with protozoa or ground meat food.


Actually, the only water frog that needs a tank with a capacity of about 25 liters. The Zaire dwarf clawed frog(Hymenochirus boettgeri), also known as Congo dwarf clawed frog. These frogs grow up to 3.5 cm in length, so they are relatively small. Despite this, they require a reservoir with a fairly large bottom surface, so a typical cube is unlikely to be suitable. The tank should be planted quite intensively. The clawed leprechaun is a predator and should be fed live or frozen insect larvae. It is not recommended to keep shrimps or snails in one tank. Unless their destiny is to be food.

The diving bell spider

The diving bell spider (Argyroneta aquatica) is the only spider that spends its entire life underwater. Due to its small size (it grows to 1.5 cm) and high mobility, it can be a real attraction in a nano aquarium. It requires clean and not too warm water and quite tall plants, between which he will be able to attach his “house”. A cover is needed on the tank to prevent it from escaping. The diving bell spider should be fed with insect larvae, preferably alive. Better not to keep with fish (especially fry) or shrimps.

Tropical Fish

You may now ask- why are fish at the end of this list? The answer is easy- fish need space to swim and although there are species that would live long in a nano aquarium, it’s not recommended to breed them in the minimum of their requirements. Another inconvenient matter is maintaining the stable water parameters and if this condition is not fulfilled, fish usually react drastically. When deciding to keep fish in a nano aquarium, choose the tank as long as possible so that at least one of the dimensions gives the fish the impression of space. If  you want to keep fish in your nano fish tank, choose species that have small size and don’t have high space requirements The best choice will be a fish species that live singly or in small groups (not in shoals) in their natural environment e.g.:

Hyphessobrycon Amandae

Danio margaritatus

Paracheirodon innesi

Paracheirodon simulani

Axelrodia riesei

Betta splendens

Heterandria formosa

Corydoras habrosus

Corydoras pygmaeus

Corydoras panda

Poecilia reticulata

Poecilia wingei

Nano aquariums – are they for everyone?

Although smaller aquarium systems seem much simpler than large fish tanks- it is exactly the opposite. First of all – in a small tank, it is much more difficult to maintain stable water parameters. A small amount of liquid heats up or cools down faster, becomes contaminated easily, and even a small change of equipment or the introduction of a new occupant can drastically change the water chemistry. If we plan to breed quite demanding fish, in such a small tank, efficient filtration and regular water changes will be necessary. A great danger of nano aquariums, and a tragedy that often occurs, is the “boiling” of the tank together with its compactness, when under the influence of external factors (high ambient temperature, the sun, heat source nearby the tank) the water temperature in the tank quickly increases from a few to a dozen degrees, thus leading to the death of the inhabitants. Of course, sudden hypothermia is equally probable and equally dangerous.

If you plan to have a successful nano aquarium and not just a mini aquarium, you must take into account a lot of work on the aesthetics, which is the most important. The continuous formation of the underwater landscape requires a lot of patience and precision. Although ready plant kits are available on the market, they also require constant care.

How to set up the nano aquarium?

As always, firstly the vassal should be suitable for the future inhabitants. While buying it, be careful about its shape because producers have varied ideas and not all will be proper for live beings. The next thing is the substrate that is a very important part of such a reservoir. Firstly, due to the limited possibilities of subsequent fertilization of plants (little space, frequent water changes), the substrate must contain as many nutrients as possible. Second – because nano aquariums are more “vertical” – the substrate (often consisting of colored layers) is an important decorative element. Therefore, instead of common gravel in nano aquariums, substrates with different properties and appearances are used.

Now begins precisely aquascaping, that is the formation of an underwater landscape consisting of plants and decorative elements such as rocks, stones, or pieces of wood. In fact, it all depends on our preferences, although there are a lot of tutorials on the Internet that can be a guide to the techniques used and current trends. The most important thing in such a small space is “planning the future” – how the plants will grow, how we will repair any damage, etc. – so that the care of the tank is easy, and the aquarium itself remains aesthetic at every stage. Never should any aquatic creature be allowed into a brand new aquarium before nitrates have been controlled and removed. See here

The maintenance and daily care of nano aquariums are the same as for a larger tank, except that everything is more frequent. For example, it is best to change the water once a week and preferably around 1/3 of the tank capacity. Similarly, due to unstable parameters, it is worth performing aquarium tests as often as possible. We must also be sure to trim any plants to ensure they don’t take over.

Although many aquarium manufacturers advertise such “little things” as something easy and for everyone – this is definitely not true. A nano aquarium allows you to save space and will fit in absolutely any room, and its installation is relatively cheap – but, as usual, apart from the pros, there are also disadvantages. In the case of nano aquariums, it is a need for systematic work and continuous monitoring of the tank, as well as needing a considerable amount of knowledge. Despite this, nano aquariums are becoming more and more popular every year, and the projects presented at various exhibitions and competitions make a great impression. 

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