The practice of creating a biotope aquarium involves simulating a natural aquatic environment. A true biotope fish tank is a cross section of the exact environment and it’s inhabitants. In reality most biotope aquariums use a specific natural environment as a template from which an approximation is developed. Let’s face it, muddy water and leafy substrates might be elements of some biotopes, but hold little appeal for the home aquarium.
For many aquatic hobbyists the appeal of biotope aquaria stems from a passion for collecting. Building up a “set” of inhabitants and plants is similar to seeking out and acquiring parts of a tea set or basketball card collection.
From a practical perspective making a biotope aquarium can simplify water chemistry choices. By choosing fish and plants from the same environment it is only logical that they will live best with the same pH, hardness and temperature.
Aquarium fish and plants can also engage in more natural behaviors. Flora and fauna that has co-existed together through time can continue with the relationships they have come to rely on in nature. This can apply to feeding behaviors where a fish eats a plant natural to it’s own tastes or preys on other fish which are found in their original environment. Other behaviors such as breeding can be complemented through the correct substrate which may be integral to reproduction.
The key to a successful biotope aquarium is meticulous research and planning. Not only should a geographical region be concentrated on, but a particular water form (lake, river, stream etc.) within the region. After identifying the natural fish and plant choices available, the individual behaviors should also be considered. For example inhabitants with a predator prey relationship will be unsuitable for all but the most dedicated biotope aquarist.
New Guinea River
Brackish Mangrove Estuary
Central American River
South American Blackwater Stream
Blackwater ponds, creeks, and rivers originate in the rain-forest. In the slow-moving waters, acids are leeched from decaying vegetation creating very transparent, tea-colored water. These waters have almost no measurable water hardness and an acidic pH.
The substrate in blackwater habitats is typically leaf litter over a base of fine clay or sand. Decaying wood and plant matter is common especially in flooded igapo forest. There are many submerged terrestrial plants, many of which retain most of their leaves.
pH: 4.5-6.5, 0-4 dH, 81-86 F (27-30 C)
Furnish the tank with bog wood and a dark, fine gravel substrate.
There can be subdued lighting and still water.
Peat filtration is recommended.
Sword plants, Heteranthera, Ceratophyllum, Vallisneria, Cabomba
Discus, Angelfish, Dwarf Cichlids, Tetras, Hatchetfish, Corydoras, Farlowella, Loricarids.
New Guinea River
New Guinea has fish fauna unlike that of Southeast Asia.
New Guinea’s fish most resemble those of Australia for good reason, millions of years ago they were part of the same land mass.
The dominant species in the aquarium trade from New Guinea are Rainbowfish.
pH 6.5-7.1, 4-8 dH, 75-77 F (23-25 C)
A tank with large open swimming areas is suggested for rainbowfish.
The tank should have areas of dense vegetation and bright lighting.
Use a sand substrate.
Vallisneria, Aponogeton, Ceratopteris, Bolbitis
Rainbowfish, Gobies, Australian Arowana, Arius catfish
Southeast Asian Blackwater Pool
Creeks and streams originating from deep in the rainforest are often blackwater.
With decaying plant vegetation and few, if any, mineral sources, the water is acidic and very soft.
This environment provides a home to many species of plants and fish.
pH 5.5-6.5, 0-4 dH, 81-84 F (27-29 C)
The tank should be densely planted with a fine gravel or clay substrate.
Use wood to create hiding places and use peat filtration.
There should be little surface current.
Cryptocoryne, Nymphaea, Eleocharis
Gouramis, Bettas, Rasboras, Loaches, Glass Catfish, Cyprind sharks, Flying Fox
See my Asian Blackwater Tank Build HERE
Mangrove swamps are found through the world where freshwater rivers come in contact with the ocean.
The result is a tidal region with varying salinity and water conditions.
The tides affect some of the types of fish present in the estuary, although fish termed ñbrackish water species” remain no matter the condition.
pH 7.2-8.0, 10-20 dH, 75-82 F (24-28 C), 1.006-1.015 specific gravity.
The tank should have a coral sand substrate.
Use wood and roots to recreate the mangrove roots of the swamp.
Use an efficient filtering system, because brackish water fish are heavy eaters, yet sensitive to water pollutants.
One popular brackish-water set-up is to leave the tank only half full with water. A sandy beach is constructed and potted mangrove seedlings grow above the water surface. Such a set-up allows an aquariast to observe unusual behavior from brackish species such as Mudskippers and Archerfish.
Few plants can tolerate brackish conditions besides the mangrove.
Java Fern appears to be one of the only aquarium plants suitable for a brackish water tank.
Mangrove seedling can be kept in pots as long as the bulk of the plant is out of the water.
The Mangrove will require frequent pruning to keep it small enough for the aquarium.
Mudskippers, Archerfish, Scats, Monos, Tiger fish, Puffers, Gobies, Glassfish, Halfbeaks, Arius catfish, and Celebes Rainbowfish.
Central American River
Central America is rich with rivers flowing from rainforests and highlands. These rivers are abundant with river shrimp which provide a strong food base for larger fish like cichlids. The cichlids in these rivers are generally not as territorial and aggressive as those of the Central American lakes.
Often Central American rivers are relatively clear as they flow out of the highlands, sometimes blueish or greenish in color with a moderate amount of dissolved minerals. In the lowlands these rivers become increasingly muddy, especially in areas where there has been deforestation (i.e. much of Central America) and after rains.
Typically these rivers are rocky with sand or rock substrates. In rainforests there may be dense plant growth along the edge of the river with some plants rooted underwater but growing out of the water.
The current varies greatly in rivers — from still backwaters/ponds to swirling eddies to roaring whitewater rapids. For this biotope I suggest low to moderate current.
For a Central American biotope you can either go with an “aggressive” tank with Central American cichlids or a typial community tank or livebearers. It’s not a good idea to mix the two since livebearers are often a natural food source for wild cichlids.
pH: 7.0-7.8, 5-10 dH, 72-79 F (22-26 C)
The tank should be large with open swimming areas, submerged wood, river rocks, and a fine gravel or sand substrate. There should be a moderate current created by a filter that can handle large fish that consume lots of food.
The tank should be brightly illuminated.
Live plants will not last long with rough cichlids. An alternative is plastic plants. Rocks can be used to create territories and shelters for cichlids. Be sure rocks are well anchored since Central American cichlids are active diggers.
Vallisneria, Cabomba, Limnobium, Myriophyllum, some species of Sword plant
Remember that live plants will likely be thrashed (both eaten and uprooted) by many Central American cichlid species.
River Cichlasomines, Livebearers, Astyanax, Loricarids, Pimelodids
South American Blackwater Creek
pH 5.5-6.5, 0-4 dH, 79-84 F (26-29 C)
Use fine gravel, sand, or clay for a substrate.
Ideally, woody material should be the most prominent decoration in the tank. Use scattered Amazon swords and reedy plants like Vallisneria.
Lighting should be subdued and filter outflows placed to create little current.
Sword plants, Vallisneria
Discus, Angelfish, Dwarf Cichlids, Tetras [Hemigrammus, Hyphessobrycon, Boehlkea, and Thayeria], Hatchetfish, Corydoras, Pimelodids, Loricarids.