In the pursuit of attractiveness aquariums are set up with a large number of colorful fish, with nice, dense vegetation arranged in beautiful carpets and with proper lighting to expose all colors as much as possible. However, an aquarium should first create the best possible – i.e. as close to natural – conditions for its inhabitants as possible. This by no means means means that it cannot be decorated spectacularly, which is best demonstrated by the extremely intriguing biotope aquariums.
A biotope (place, region) is an environmental part of an ecosystem that, together with a biocenosis (population of plant and animal organisms – editorial added), forms a coherent ecosystem. The definition of a biotope is therefore close to the concept of a habitat. In simple terms, we can say that a biotope is nothing more than a habitat inhabited by a given set of organisms.
Each biotope has its own unique character and is inhabited by specific species of living organisms. Over thousands of years animals and plants have adapted to specific environmental conditions. Therefore, all living creatures (as well as all populations of creatures) have individual preferences for habitat conditions, such as water chemistry, substrate type, water velocity, temperature, light intensity, competition and access to food, and the presence of predators.
A biotope aquarium is only an attempt to reflect the conditions of the habitat. It is also called environmental aquarium, which fully reflects its character because the aim of such aquarium is to reproduce a complete ecosystem transferred from a given area – including physical and chemical conditions, typical plant and animal populations and sometimes even microorganisms. Every detail is taken into account in this case. The aquarist should therefore acquire extensive knowledge of the ecosystem to be exposed. A properly set up biotope aquarium, on the other hand, guarantees a nice aesthetic experience and gives satisfaction from the possibility of observing fish behaviour in their almost natural environment.
The natural environment in which the fish live is usually relatively simple and harsh. In case of waters of African biotype, e.g. the famous Lake Tanganyika located in East Africa in the area of the Great African Trench, it is mainly stones, smaller or larger pieces of rock covered with algae that fish feed on and sand. However, creating an interesting composition and using an appropriate background and lighting, we can be the witnesses of an interesting spectacle, whose main participants will be endemic species of fish from Tropheus family, appearing in more than ten color varieties.
Taking into consideration the color of the water, specificity of the environment and organisms occurring there, the Amazon River and its tributaries can be classified into whitewater, blackwater and clearwater. These types of watercourses have become the benchmark for aquarists in creating aquaria of South American biotopes.
The waters of the Rio Negro – the largest left tributary of the Amazon – are nearly black, and additionally low in nutrients and very acidic due to the high content of humic acids released from leaves, trees and shrubs falling into the river. They are characterized by a lazy current and an almost complete lack of vegetation. It is a biotope that is often recreated by aquarists, probably due to its aura: dark, gloomy and mysterious.
The water in this type of aquarium should be brown, which can be achieved with peat, tree bark or alder cones. The tank should be sparsely lit and the current should not be too strong. Use fine sand as a substrate. For the arrangement you can still use roots, branches, pieces of wood or leaves. You can place schooling fish such as the top-swimming Silver Trout (Gasteropelecus sternicla), the deep-swimming Bleher’s Wiggler (Hemigrammus bleheri), the bottom-occupying Corydoras duplicareus Sands or the wild variety of the Clawfish Symphysodon tarzoo that moves stately through the tank.
The second extremely inspiring biotope in South America are the so-called clearwaters. To these waters belong the upper sections of the Amazon and its tributaries, because most rivers or streams carrying white water have their beginnings in the Andes. Clearwater rivers are characterized by exceptionally clear water, which is influenced by the fact that they run through ground that is resistant to washing out. They are usually rivers with fast current, slowing down only on bends and backwaters.
When recreating the biotype of clear waters in an aquarium, we can stimulate our imagination and undertake a slightly more difficult task – to recreate a stream with a spring, live current and sandy bottom. An interesting arrangement can be created using tree stumps and roots, pebbles and plants that can be also used for planting the upper part of our tank, leaving at the same time plenty of free swimming space for shoal fish from that region, e.g. we can also fill up the upper part of our tank with such fish as black neon (Hyphessobrycon herbertaxelrodi), Amazonian hockeyfish (Thayeria boehlkei), Brazilian earthworm (Geophagus brasiliensis) or even – if the tank is large enough – the spectacular Xingu river stingray (Potamotrygon leopoldi).
In an aquatic system we distinguish between different biotopes with different environmental conditions and types of living organisms:
– a biotope with sand, stones and water of high hardness;
– A lake shore biotope with wood, leaves and acidic water;
– A river biotope with muddy bottoms and aquatic vegetation;
– a stream biotope with fast current and well-oxygenated water.
Deciding on this kind of aquarium, we have many biotypes to choose from and plenty of possibilities for its arrangement. Everything depends only on our ambition and creativity.
Distinctive photo: Flickr
