Middle course of the Rio Negro River, a forest canal, Santa Isabel do Rio Negro, Brazil

19th place in Biotope Aquarium Design Contest 2017

russian_federation Russia. Anastasia Chistyakova

Volume: 120 L
Dimensions: 78x38x41 cm
List of fishes: Paracheirodon axelrodi
List of plants: Eleocharis acicularis
Description of decorations: Mangrove driftwood, UDeco Coral Driftwood, UDeco Chinese Driftwood in shape and color are similar to those presented in the nature biotope; UDeco River Light sand, 0.1-0.6 mm, leaf litter.
Description of equipment: Aquael “Asap 500” internal filter for aquarium, 50 – 150 l, 500 l/h, fluorescent lamps Power Glo T5 24 W 55 cm
Water parameters: Temperature 24°С, pH – 5,6, gH – 8

Description of the area surrounding the biotope: The Rio Negro river, being the left tributary of the Amazon, starts under the name the Guainia river at 2° of north latitude in Colombia, flows through Venezuela, changes its eastern direction to the south, takes the left sleeve of another largest river of South America, Orinoco ( which starts in the Guiana highlands) through the channel Casiquiare. The right tributary of the Rio Negro, the Uaupes River, starts in the foothills of the Western Cordillera. Rio Negro flows from northwest to the southeast of Brazil along the Amazonian lowland, flowing into the Amazon below the city of Manaus, and enters the Amazon river basin. Almost the entire river basin is located on the territory of Brazil. In the upper reaches, up to the town of Castanheiro, there are many rapids, then the river flows along a flat territory, from which it collects rainwater through numerous tributaries. Only a few of them are classified as large, others are short and small. The river flows through rain forests, where branches of trees hang over the water and are partially submerged in it. The current is slow, the water is poorly lit by the sun.

Description of the underwater landscape of the biotope: The river carries a soil washed from the Guyanese heights (the Guiana highland). The substrate is sandstone, fine sand is yellowish white. As the Rio Negro flows through the rainforest, there are many branches, driftwood, fallen leaves in the water, the bottom is covered with organic matter, which creates a unique image of the river.

Description of the parameters of the habitat: The Rio Negro river is called black because of the color of its water. It is really very dark and has a pronounced brown pigmentation. The dark color of water is given by humic acid, which is formed as a result of incomplete decomposition of phenol-containing compounds that enter water from fragments of plants that cover river banks. The water is transparent with a depth of visibility of about 2 m. Shallow water has a lot of driftwood and a thick layer of fallen leaves; these are the most characteristic and inalienable elements of the biotope. Tree trunks and tangled roots create blockages in which some fish hide from enemies, while others, on the contrary, wait for their victims. There are almost no water plants here, only algae. But during the rainy season, when the water rises and floods the vast floodplain, entire underwater forests are formed, the so-called igapo (igapo is Portuguese for “swamp”), a real expanse for the inhabitants of the river. The water is very soft, because the river takes water from rain, and acidic, because of the saturation of humic acids formed during the decomposition of plant remains. Water parameters of the biotope: Temperature 23-26°С, pH – 5.5-6.8. The total hardness does not exceed 1° dGH, and the carbonate hardness does not exceed 0.3° dKH.

List of fishes: Paracheirodon innesi, Paracheirodon axelrodi, Hemigrammus bleheri, Apistogramma pertensis,  Apistogramma hippolytae, Ancistrus dolichopterus L-183, Dicrossus filamentosus, Pterophyllum sp., Nannostomus trifasciatus, Nannostomus marilynae, Mesonauta insignis, Carnigiella strigata, Cichla orinocensis, Cichla temensis, Uaru amphiacanthoides.

List of plants: Eleocharis acicularis, Echinodorous horizontalis, Echinodorus tenellus, Eichhornia crassipes, Сabomba,  Salvinia oblongifolia, Limnobium laevigatum.

Threats to the ecology: The aquarium was set up to attract attention to the Rio Negro river. It feeds the Amazon with its own waters. The river is unique, because it is connected through the Casiquiare River with the Orinoco River and is a natural channel between Orinoco and the Amazon, so some species of fish can migrate throughout the water area of both rivers. Paracheirodon axelrodi is a commercial aquarium fish and is subject to a massive catch. The Rio Negro basin, like the entire Amazon basin, is threatened today due to continuous deforestation, uncontrolled expansion of pastures and activities of gold miners. In addition, in the state of Amazonas there is a deposit of niobium: Seis Lagos, not far from the city of San Gabriel, the port on the Rio Negro river. This is the largest known niobium deposit in the world today. There is a danger of contamination of fresh water, which will lead to the disappearance of a number of species and the imbalance in the ecosystem.

Sources of information: https://vk.com/video-52983980_171661452?list=51366eca94500a704c, https://vk.com/video-52983980_166088871?list=ad3aea0d7de3e3dc36, http://fr.youtube.com/watch?v=uQNP25Xd7wI, https://vk.com/video-52983980_169821723?list=ada4ed7f2c73b32c87, https://vk.com/video-52983980_171772388?list=af511842f4b91ab099, http://myaquaclub.ru/fish/characidae/147-paracheirodon-axelrodi, http://aquamir-za-steklom.ru/akvariumnye-rasteniya/katalog-akvariumnykh-rasteniy/yeleokharis-sintyag.htmlhttp://www.seriouslyfish.com/species/paracheirodon-axelrodi/