Rio Negro, beauty of the dark

The 50th place in the qualifying stage of the Biotope Aquarium Design Contest 2014

USA. Danett Williams

Volume: 110 L
List of fishes: Nannostomus trifasciatus, Paracheirodon axelrodi
List of plants: Echinodorous horizontalis, Eichhornia crassipes, Salvinia oblongifolia
Biotope description: In order to support the green industry of cardinal tetra farming in the Amazon which protects its powerful waters, cardinal tetras were employed in an aquarium representing a microcosm of the Rio Negro. The waters of the largest blackwater river worldwide, are acidic and warm. On the shore of the Rio Negro, Echinodorus horizontalis may be found. However, due to heavy rains it is found fully submerged amongst leaf litter. The tannin stained waters constrain light for aquatic life, leaving little more than floaters amidst the top of the water in this particular area. Cardinal tetras and Three Lined Pencilfish swim amongst the leaf littered bottom wherein the sand is stained with humic acid from decomposing plant matter. The waters are full of fallen branches from the rainforest. Each branch was mindfully selected, shaven, carved, washed, and placed. Care was expended in collecting leaves and boiling them to extract their tannins. Realistically, much like portions of the blackwater Rio Negro, the water is slightly murky. However, a shaft of light is able to shine through.