As a natural aquarium, also called Japanese natural aquarium, the freshwater aquariums are referred to, in which aquarium plants have at least an equal role to the cultivated in the aquarium fish species. The aim of the aquarist is to create landscape-like spaces using aquarium-suitable decoration material such as moorland roots and stones. Despite the somewhat misleading name, it is not a biotope aquarium. This branch of aquaristics was significantly influenced by the Japanese photographer and aquarist Takashi Amano.
Typical for the planting of a natural aquarium is an extensive and dense planting of the foreground with small aquarium plants. This gives the aquarium a certain visual depth. The free space in the aquarium is a central design element and is strongly emphasized. Amano generally uses very soft, low-carbon water with low nitrite and nitrate concentrations. The side walls are almost always free of decoration. On the back of the aquarium, a black or deep blue foil is often glued on.
The distinction to the Dutch plant aquarium is difficult. In the Dutch plant aquarium, the plants are used in a garden bed similar to the aquarium. Generally, many different plants are maintained. A natural aquarium, on the other hand, can consist of a "meadow" of grassy sword plants or a short jam moss, for example, from which a wood root protrudes like a tree. Other typical plants in Japanese natural aquarium are tongue leaf, pond liver moss and needle lime.
Both aquarium types are often dependent on carbon dioxide fertilization because of the large role played by aquarium plants.
