Amazonas, Manaus, Brazil, Rio Negro River blackwater biotope

72nd place in Biotope Aquarium Design Contest 2017

turkey Turkey. Emrah Kahyaoğlu

Volume: 225 L
Dimensions: 100x50x45 cm
List of fishes: Apistogramma agassizii, Biotodoma cupido, Pterophyllum scalare, Hyphessobrycon herbertaxelrodi
List of plants: Cabomba aquatica
Description of decorations: The bottom layer is coco peat with Sera super peat and 1-2 mm natural creek on dried oak leaves. The dry oak plane tree is the new world leaves. Mangrove tree and fruit (plum tree).
Description of equipment: Eheim professionel 4+ 600, Eheim Jager 300W heater, Eheim air pump 400, 5 pieces of 5W spotlights. Reverse osmosis system.
Water parameters: Temparature is 27°C, pH is 5.0, KH is 3.0 dH, GH is 8 dH.

Description of the area surrounding the biotope: Rio negro, the second largest branch of Amazon, is 2,250 km long and enters the Brazilian Rio Negro, forming the Venezuela border from the Guainia river rising from the rainforest of the Colombia, Orinico river. White river from the other side near Manaus, Solimões, joins to create Amazon. The mineral content of Rio Negro’s water is extremely poor, the conductivity is as low as 8 μS and it is extremely acidic, the pH changes from 2.9 to 4.2. Rio Negro, the largest black water river in the world, is only the second according to Madeira. It provides about 14% of the annual release of the Amazon. Negro’s inland waters are due to And Mountain skirts. Above, flood season occurs between May and September and peak is in July. Rio Negro flood waters run from February to July, with the highest water levels in June. Along the main body of Rio Negro, there are numerous human environments, including more than 600 islands in the lower and central parts of the river. There are many floodplains along the canals and caverns (campinarana). During the dry season there are large sandy beaches throughout the rivers. The river is rocky with pebble stones and rocks. Rocky outcrops and cataracts prove Guiana shields in the mid-point of Negiana. Black waters are home to large areas of the igapó forest, influenced by rivers and ecological rivers. This forest type is found on land which is seasonally flooded every year and is poorly sandy, oligotrophic or nutritious. In the Rio Negro basin there are more than 685 species. Of the 11 orders, Characiformes and Siluriformes represent about 74% of species. At least 20 species are known; one of them is a new kind of family. The total species richness is roughly between 800 and 900 species, with more than 90 species considered endemic in the Rio Negro basin. Rio Negro is home to more than 100 species sought for aquarium trade. The rainbow of some species, such as the endemic cardinal tetra (Paracheirodon axelrodi), may be an adaptive feature of Negro’s land water.

Description of the underwater landscape of the biotope: Strong acidity also results in a relative poverty of these waters, due to the shortage of nutrients accentuated by the difficulty with which the sun’s rays penetrate deeply, making it even easier to develop an adequate aquatic vegetation of primary production (photosynthesis) of the ecosystem.

Description of the parameters of the habitat: Rio Negro is 2-3 degrees warmer than white water or clear water due to the presence of black water. This is the reason why Solimões does not mix with this river. Solimões is faster, cooler and more prosperous, its waters flow up to 22 km at 6 km/h and the hot and slow waters of Rio Negro flow at a slower 2 km/h and the temperature is about 28°C. Temperature is 27-28°C, pH is 4.5-5.0, conductivity is 10-15 μS, trace elements are Na (mg/L) 0.380 ± 0.124, K (mg/L) 0.327 ± 0.107, Mg (mg/L) 0.114 ± 0.035, Ca (mg/L) 0.212 ± 0.066, Cl (mg/L) 1.7 ± 0.7, Si (mg/L) 2.0 ± 0.5, Sr (μg/L) 3.6 ± 1.0, Ba (μg/L)8.1 ± 2.1, Fe (μg/L) 178 ± 58, Mn (μg/L) 9.0 ± 2.4, Cu (μg/L) 1.8 ± 0.5, Zn (μg/L) 4.1 ± 1.8, Total P (μg/L) 25 ± 17, Total C (mg/L) 10.5 ± 1.3, HCO3-C (mg/L)1.7 ± 0.5, Al (μg/L) 112 ± 29.

List of fishes: Osteoglossum spp. (Osteoglossidae); Anostomus taeniatus, Leporinus fasciatus (Anostomidae); Paracheirodon axelrodi, P. simulans, Hemigrammus bleheri, H. schmardae, H. vorderwinkleri, Hyphessobrycon socolofi, Elachocharax georgiae (Characidae); Copella nattereri, Pyrrhulina brevis, Nannobrycon unifasciatus, Nannostomus beckfordi, N. eques, N. unifasciatus (Lebiasinidae); Carnegiella marthae (Gasteropelecidae); Colossoma macropomum, Piaractus brachypomus, Serrasalmus nattereri (Serrasalmidae); Boulengerella lateristriga (Ctenoluciidae); Corydoras robineae, Dianema urostriata (Callichthyidae); Phractocephalus hemioliopterus, Perrunichthys perruno (Pimelodidae); Peckoltia pulchra (Loricariidae); Aequidens diadema, A. pallidus, Apistogramma agassizii, A. gephyra, A. gibbiceps, A. hippolytae, A. pertensis, A. regani, Astronotus ocellatus, Cichla ocellaris, Nannacara adoketa, Pterophyllum scalare, Symphysodon discus (Cichlidae); Eigenmannia virescens (Rhamphichthyidae).

List of plants: Cabomba aquatica, Ceratopteris pteridoides, C. thalictroides, Echinodorus horizontalis, E. tenellus, Eichhornia azurea, E. crassipes, Hydrocleys nymphoides, Hydrocotyle leucocephala, Limnobium laevigatum, Ludwigia helminthorrhiza, Mayaca fluviatilis, Phyllanthus fluitans, Pistia stratiotes, Salvinia auriculata, Utricularia gibba.

Threats to the ecology: The region holds the southern half of the Puinawai Nature Reserve in Colombia. The protected areas in Brazil are the Mamirauá Sustainable Development Reserve in Purus Várzea eco Region, the Aman Sustainable Development Reserve and Jaú National Park. The forest is largely uncomfortable and relatively stable, but there are high levels of mining, logging, agriculture, hunting and fishing throughout the rivers. There is no road close to Manaus in the region, but the rivers carry a lot of boat traffic. Urban development in the Manaus region causes deforestation and pollution. In the border area between Colombia and Brazil, the river coast is being demolished by gold miners. The river causes uneven tree logs along the coast.

Sources of information:,,, Heckel 1840 – Kullender 2003 (biotodoma cupido),

Comments of the members of the jury of Biotope Aquarium Design Contest 2017

Maybe straight pieces of driftwood are not very aesthetic, but it is very probable for such a composition to occur in the wild (not all root systems are nicely curved and optically balanced according to golden ratio). What I like in this tank is dimmed light, lots of hiding places for the fishes, and very good bottom, covered with partly decayed leaves.

Piotr Kierzkowski (Poland)