The tributaries and floodplains of the Amazon basin flood spectacularly, and the forest itself is several feet under water at certain times in the year. The water is full of broken wood, terrestial plants, and considerable leaf litter. As the water subsides, many fish are left in pockets of slowly evapourating water. A wide range of popular aquarium fish live under this annual cycle and it is easy to create a spectacular biotope aquarium. Because of this 'opening up' of the Amazon, many of its numerous species could end up in any of the below biotopes, though this is not always the best way to keep and/or breed them.
Cardinal tetra (Paracheirodon axelrodi)
Aquarium Setup: Lots of wood, roots and aquatic vegetation. Wood should represent tree roots, as found in the flooded forest. Amazon sword (Echinodorus) and Vallis (Vallisneria). Areas of fast flowing and still water.
Substrate: gravel
Water Conditions: slightly acidic to neutral
Temperature: 26-30 C
Typical fish:
Catfish (Corydoras, Ancistrus , Farlowella, Pimelodus)
Characins (Tetras, Piranhas, Hatchetfish, Pencil fish)
Cichlids (Discus, Eartheaters, Oscars, Angelfish, Laetacara)
Aquarium Setup: Densely planted in areas with faster moving open water (Echinodorus) and Vallis (Vallisneria)
Substrate: gravel or sand
Water Conditions: slightly acidic to neutral
Temperature: 24-29 C
Typical fish:
Catfish (Corydoras, Ancistrus, Farlowella, Pimelodus)
Characins (Tetras, Hyphessobrycon, pencil fish)
Cichlids (Apistogramma, Papiliochromis (ram), Mesonauta, Uaru)
Killifish (Rivulus, Pituna)
Rivulus xiphidius PK15 (French Guiana)
Aquarium Setup: Water should be peat filtered or have considerable tanin from the submerged wood and leaves. This biotope has few plants, (maybe Amazon sword (Echinodorus), Vallis (Vallisneria) and duckweed)
Substrate: gravel, sand, or even peat with leaves and wood
Water Conditions: very soft and acidic to slightly acidic
Temperature: 24-29 C
Typical fish:
Catfish (Corydoras, Ancistrus, Farlowella, Pimelodus)
Characins (Tetras, Hyphessobrycon)
Cichlids (Apistogramma, Papiliochromis (ram), Mesonauta, Uaru)
Killifish (Rivulus, Pituna, Simpsonichthys)
The biggest killer of tropical fish is overfeeding. Uneaten food decays and pollutes the water, even with adequate filtration. Adult fish should remain unfed one day each week, and almost all commonly available species will be completely fine if unfed during a two week vacation