In freshwater aquaristics, a nano tank is usually understood as a glass tank undercutting the volume of a standard aquarium (60 x 30 x 30 cm) of 54 liters. Surprisingly enough, there is no German law for keeping ornamental fish, but there is an expert report called "Minimum requirements for the keeping of ornamental fish", which was compiled by the "Working group aquaristics in the BNA" (Federal Association for nature, animal and species protection) in cooperation with various associations. Therein the keeping of ornamental fish is recommended from 54 liters upwards. In other countries, such as Austria, this size is even set by law as the minimum size.
Popular nano-aquariums include Dennerle's square Nano Cubes made of glass. They are pretty popular among shrimpkeepers. Because of their panoramic style, glass tanks in a more elongated design are better suitable for aquascaping, e.g. the Mini M by ADA or the Scaper´s Tanks from Dennerle. Their rather small dimensions make them less suitable for the keeping of fish (with the exception of the Betta splendens), invertebrate fauna like snails and shrimp are predestined, though. For this, these beautiful aquariums are almost perfect. Especially in recent years, there’s been a proper hype surrounding the keeping of dwarf shrimp like Bee Shrimp or Neocaridina in such a Nano aquarium.
These small tanks can be equipped with the suitable internal or external tech, and can be put in various places in your living space because of their small weight and size. This can be the desk, a dresser or a little spot on top the kitchenette. A floor unit for a nano aquarium sure is possible and might look cool, but not really necessary.
Incidentally, the term Pico means an extremely small nano-aquarium with a capacity of less than 10 liters. Due to their small size, these are generally operated without technology and without animal population. They then serve as pure plant aquariums.
The myth of the unstable system in a small aquarium
Many long-established aquarists are sure, that the bigger the tank is, the more stable its ecosystem will work. Due to this, many beginners are given the advice to start their hobby with a bigger tank. However, one can confidently consider this idea obsolete: There are well and poorly running ecosystems even among the large aquariums. The required technology has been scaled down so much in recent years that it can easily be used in a small nano aquarium. Lighting, filtration, heaters and other components have been available as well-suitable accessories for small aquariums for years.
In this respect, nano aquaria can be very much recommended for beginners. They also have their own advantages. Due to their small size, running costs such as water and electricity are lower, as well as the initial costs for decoration, substrate und aquatic plants. Fertilizer, food and maintenace products have been made available in smaller containers as well which are much more befitting to a nano aquarium than the bulk packs from the days of old. Thanks to their compact dimensions, nano aquariums can be integrated almost anywhere in the living space, even with very limited room, and they do not look as bulky and massive as larger glass tanks with hulking floor units.
Aquatic plants for a nano aquarium
A nano aquarium can be excellently set up as a plant aquarium or aquascape. Especially thanks to nature aquaristics, smaller, ground covering plants and mosses have become very popular. By now, they have become part of the standard range of any well-stocked specialist shop. Here’s a little overview of aquatic plants, which fit a nano aquarium well:
This moss has lengthy fronds that are shaped like little Christmas trees. It can attach to surfaces such as wood and stone. In sufficient light, it grows compact, with sometimes slightly drooping shoots.
Hemianthus callitrichoides "Cuba"
Dwarf Baby Tears is one of the smallest aquarium plants. It is often abbreviated as "HCC", which is short for its species name Hemianthus callitrichoides "Cuba". A more sophisticated plant with roundish light-green leaves, with a creeping growth habit. If sufficient light and nutrients are available, HCC will produce visible oxygen bubbles.
The coral moss has really tiny leaves and therefore is ideal for a nano aquarium. This special moss grows on wood or stones and forms roundish cushions. Coral moss grows slowly, but nevertheless requires a little more light and nutrients as well as good CO2 supply for healthy growth.
Fissidens fontanus, also called Phoenix Moss, is a uniquely beautiful moss. The leaves are very small, short and delicately shaped like feathers. This moss forms roundish cushions and can grow on decoration and substrate particles. A more sophisticated moss, that needs a good CO2- and nutrient supply in order to grow well.
Eleocharis sp. 'Mini'
An excellent ground cover for a grass-like lawn in your nano tank. The plant propagates through runners, albeit at a rather slow speed (more like walkers amirite?). The thin stalks are light-green. Eleocharis sp. 'Mini' has a lower habit than other Eleocharis species. Thus, the plant is well-suited for a small aquarium.
Hemianthus glomeratus as emerged potted ware.
The Manatee Mudflower, thanks to its small leaves, is a stem plant, well-suited for a nano aquarium. It forms dense shrubs and can be used in the middle or in the background. An all-encompassing fertilization with micro and macronutrients as well as CO2 should not be missing for this plant to grow fast and vital.
This is a very small variant of the water trumpet. The green leaves are slightly lanceolate. Like almost all other crypts, this plant is rather undemanding, but sufficient light and a soil rich in nutrients will make the dwarf water trumpet grow better. Cryptocoryne parva is great for use in the middle- and foreground of a nano aquarium.
During the last couple of years, the different Bucephalandra-forms have become more and more popular. These slow-growing epiphytes are fairly undemanding and small-scale. The many different leaf shapes and colors make them a popular collector's item. They can be used to green stones or driftwood. A closer look at the species Bucephalandra can be found here.