Rio Caurés, Igarapé Cajarí, tributary of Rio Negro, Barcelos, Amazonas, Brazil

124th place in Biotope Aquarium Design Contest 2019

Brazil. Thiago Douglas Nobre

Volume: 128 L
Dimensions: 80×40×40 cm
List of fishes: Carnegiella strigata, Nannostomus beckfordi,Nannostomus unifasciatus,Paracheirodon axelrodi,Hemigrammus rhodostomus, Hyphessobrycon erythrostigma, apistograma,Dicrossus filamentosus.
List of plants: Rotalas
Description of decorations: Leaves and branches of mangoes (Mangifera indica L.) Goiabeira (Psidium guajava) and Jaqueiras (Artocarpus heterophyllus) Easily found in areas of the Amazon jungle, when flooded its fruit serves as food for fish.
Description of equipment: 700 L / H pump with side sump
Fluorescent Lamps 1×18W
Water parameters: temperature is 25øC, ph is 5.5, kh is 2
Additional info: side sump with excellent filtration


Description of the area surrounding the biotope: The Rio Negro is the second largest river in South America, with many tributaries. Among them the Rio Caurés which is near Barcelos.
It is located on the right bank of the Rio Negro, 405 km from Manaus (656 km by waterway).

Description of the underwater landscape of the biotope: Forests represent an important source of plankton and biofilms as natural food needed for young fish as well as for adults. In addition to providing food for fish, forests provide shelter for predators and create shade above water, avoiding overheating and even over-drying during the dry season. The soil is sandy and almost without mineral content. A large amount of litter forms a dense carpet along with the roots of the forest and flooded branches. Water carries a lot of debris. The detritus contains decomposing organic matter

Description of the parameters of the habitat: The temperature is about 23 ° C, the pH of the water is about 6 ph. During the dry season starts around May 29 and lasts 03 months, ending around September 6, the water level is reduced and warmer, the water temperature is about 28-30 ° C. Due to the low water level and the large amount of leaves and branches, the water contains a large concentration of tannins, which adds a dark color as “tea color” and the pH of the water is low and is about 3.8 and 4 , 9. This high acidity is due to the presence of large quantities of dissolved organic drainage of sandy soils. Therefore, from the point of view of ecological constraints, regions of the rivers of black water are usually associated with podozoic soils, more fragile regions of the Amazon. Nutrient poverty of blackwater rivers influences the life of fish if they sustain themselves, they obtain most of their diet of organic matter from rivers (various types of insects, fruits, flowers, leaves and seeds).

List of fishes and invertebrates occurring in the nature biotope: Pencil Fish,Hyphessobrycon erythrostigma,
Mesonauta festivus,

List of plants found in the nature biotope: Rotalas

Threats to the ecology: Dry and burned trees, devastated riverbank forests, destroyed fields, great fish mortality, are some of the damage caused by extensive forest fires in the Barcelos region. Residents of the communities report the impacts of the uncontrolled fire. In Rio Caurés, some families have already gone to the city after losing their fields and feel the difficulties in fishing.

Sources of information:

Comments of the members of the jury of Biotope Aquarium Design Contest 2019