Oxbow edge of stream in Rio Guapore drainage, Bolivia

6th place in Biotope Aquarium Design Contest 2017

 Poland. Kamil Hazy

Volume: 345 L
Dimensions: 180x60x32 cm
List of fishes: Apistogramma trifasciata 5m+5f, Corydoras sterbai 12x, Hyphessobrycon eques 40x
List of plants: Helanthium tenellum, Helanthium bolivianum, Hydrocotyle leucocephala
Description of decorations: Decorations: Driftwood and roots in shape and color similar to found in the natural biotope. Substrate: Sand 0,4-1,2mm mixed with clay and peat. Partially river sand 0,8-1,5mm
Description of equipment: Light: 40x 1W 6500K LED modules; 20x 0,7W RGB LED modules; 8x Leddy Tube 6W LED modules “sunny”; SANRISE 40W 7000K LED beam; Filtration: Eheim 2228 Canister filter (biofilter), Aquael Turbo 2000lph, Aquael Turbo 1500lph (mechanical filters, sponge only)
Water parameters: Temp : 22-24 deg. Celssius (varies day/night) ; pH 6,5 ;GH 2 ; TDS=30

Description of the area surrounding the biotope: Rio Guapore/Itenez is a 1530km long river lying at the Bolivian-Brazilian border. Unlike other rivers in the Madeira system it’s a “clearwater” right bank tributary to the Rio Mamore and drains the eastern Bolivian lowlands and southern Brazilian Shield. It originates in the Mato Grosso Plateau, Brazil and therefore variety of flora and fauna is similar to those found in the Pantanal wetlands region. Extensive areas of seasonally flooded forests and savannas, swamps, marshes, and shallow, flat-bottomed lakes creates a unique ecosystem with variety of specialized habitats. Whole area is extremely rich in flora and fauna species. Literature says there is about 600+ different fish species in Itenez drainage. Some people call Rio Guapore the most rich river in aquatic plants all over the South America.

Description of the underwater landscape of the biotope: Specified biotope represented in my aquarium shows an oxbow edge of shallow stream, with water level approx. 30cm. This type of littoral zone is full of aquatic plants submerged during rainy season, and partially or fully emersed when the rains don’t fall. Slow water movement in the oxbow area, where the flow was stronger in the past, and the encroached tree roots occur, creates perfect microhabitat for Apistogramma trifasciata group. Thick layer of dead leaves, twigs and bark gives hiding spots and variety of food sources for this species. That area is also covered with partly emersed growing stems of Hydrocotyle leucocephala, so it’s well shaded, and therefore creates safe environment for small, slower moving fish . Corydoras sterbai in the border area between zones of little stronger and slower flow search the bottom for food that comes with water. Quite large group of Hyphessobrycon eques, while searching for food, moves in the front of roots to the area with brighter light which gives perfect conditions for Helanthium species to grow densely. When not feeding, apisto males patrol their bottom districts, trying to attract females and attempting to become the “alpha male”; corys lies under the roots; tetras loosen their group ties with males displaying to attract females, and overcome rivals over their quasi-territories..

Description of the parameters of the habitat:
Water parameters varies depends of specific habitat, but water is almost crystal clear (small amount of tannins occur in the forest areas), soft and slightly acidic with parameters: pH 6,0-6,8; hardness 1 ºdH; electrical conductivity 5-20 µS/cm (to 100µS/cm in the seasonally almost drying lakes and oxbows), temperature 22-28 ºC

List of fishes:  Aphyocharax sp., Hemigrammus sp., Gymnocorymbus sp., Hyphessobrycon sp., Corydoras sp., Otocinclus sp., Apistogramma sp. and many more.

List of plants: Eichhornia azurea, Echinodorus sp. (many species), Ludwigia sp., Cabomba furcata, Myriophyllum sp., Hydrocotyle leucocephala, Egeria najas, Salvinia auriculata and many more depends of water mark during high and low water levels.

Sources of information:

• “Bleher Biotopes” book
• Catálogo das Espécies de Peixes de Água Doce do Brasil, 2007 (https://www.researchgate.net/publication/234128916_Catalogo_das_Especies_de_Peixes_de_Agua_Doce_do_Brasil)
• http://www.feow.org/ecoregions/details/guapore_itenez
• Chemistry of different Amazonian water types for river classification: a preliminary review, 2014 (https://www.witpress.com/Secure/elibrary/papers/WS13/WS13002FU1.pdf)
• CATÁLOGO DE LOS PECES DE LA CUENCA ITÉNEZ (BOLIVIA Y BRASIL), diff. authors (https://www.academia.edu/7619380/Catalogo_de_los_peces_de_la_cuenca_Itenez_Bolivia_y_Brasil_)
• Peces del Rio Mamore, L. Lauzanne, G. Loubens, Paris 1985
• www.planetcatfish.com
• www.fishbase.org
• www.discoverlife.org
• www.eol.org
• www.gbif.org
• talks with other aquarists and hobbyists from around the world