Igarapé do Daracua, Rio Negro river, Brazil

_th place in Biotope Aquarium Design Contest 2020

Volume: 54
Dimensions: 60x30x30
List of fishes: Paracheirodon Axelrodi
List of plants: N/A
Description of decorations: The substrate is sand, covered with roots, deadwood, small branches and leaves.
Description of equipment: Internal filter JUWEL Bioflow ONE 300 lph, LED lamp JUWEL PrimoLux 60 1x8w
Water parameters: Temperature is 25°C, ph is 6.8, black water
Additional info: Water change: 20 L/10 days, Lighting period: 6 hours/day
Aquarium cotton is used in the filter outpout to keep the water flow low.


Description of the area surrounding the biotope: Rio Negro is the second largest river in South America with many river tributaries that eventually end up with smaller forest streams. One of these forest streams is Igarapé do Daracua in Brazil and is named after the village of Daracua, which is located near Barcelos.
Description of the underwater landscape of the biotope: During the rainy season the water level rises and is poured into the surrounding forest. This is a time of abundance, because the fish migrate into the submerged forest where abundant food sources are found and the breeding begins. Forests represent a major source of plankton and other natural foods necessary for young fish, as well as for adult ones. Other than providing natural food for fish, forests provide them with the shelter from predators and create the shadow above water, thereby preventing overheating and even excessive drying during the dry season. The soil is sandy and with almost no mineral content. A large amount of leaf litter forms a dense carpet, along with the roots of the flooded forest and branches. Water carries a large amount of detritus. Detritus contains decomposing organic matter, including animal remains, plant residues, waste products, and bacteria and other microorganisms associated with them.
Description of the parameters of the habitat: During the rainy season (starts September 6 and lasts for 8.7 months, ending around May 29) the water is considerably colder and temperature is about 23 °C, water pH is about 6ph. During the dry season (starts around May 29 and lasts for 3.2 months, ending around September 6), the water level is reduced and warmer, the temperature of water is around 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 like “Tea color” and the water pH is low and is about 3.5-4ph.
List of fishes and invertebrates occurring in the nature biotope: Crenuchus spilurus, Nanostomus eques, Poecilocharax weitzmani, Liosomadoras oncinus, Dicrossus filamentosus, Crenicichla notophthalmus, Mesonauta festivus, Acarichthys heckelii, Crenicichla marmorata, Heros notatus.
List of plants found in the nature biotope: At the location of the biotope I have described there are no water plants, except the forest flooded plants.
Threats to the ecology: The logging of the Amazon rainforest presents a serious threat to the natural habitat of this biotope. The Amazon rainforest, besides having a great impact on the biotope , which I mentioned above, also has an impact on the overall climate of the Earth, which is why the Amazon is called the “Lungs of the World”.
Sources of information:



Comments of the members of the jury of Biotope Aquarium Design Contest 2020