Igarapé do Daracua, a flooded forest in the middle Rio Negro, near Barcelos, Brazil, 191 L

_st place in Biotope Aquarium Design Contest 2022

Volume of aquarium: 191 L

Dimensions of aquarium: 91.44×45.72×45.72 cm

List of fishes: Paracheirodon axelrodi

List of plants: N/A

Description of Decorations and Substrate: About nine pieces of small tree roots and larger tree roots were cut into individual pieces to replicate fallen branches and flooded roots. Substrates: White sand, river sand and fine river gravel. Botanicals: Catappa leaves and Mango leaves were used for tannin. Both leaves were collected under the trees near my house and were boiled before being added in the tank.

Description of Equipment: Filtration: 1x HW-604B 800l/h ,1x HW-603B 400l/h, Both filters were filled to the top with pumice that serves as biological media. Circulation pump: SOBO WP-50M 1000-3000l/h Lighting: 1x XGD-480 22w, 1x SOBO T4-80LED Other: air pump

Water Parameters: GH: ~4dGH, KH: 3-6dKH pH: ~6.4 TDS: 98mg/l

Additional Info: This biotope aquarium was inspired by “Igarapé do Daracua: Shallow Blackwater Habitat in the Middle Rio Negro” video by Reef2Rainforest.com youtube channel. 50%-60% water changes are carried out bi-weekly to reduce nitrate. There is a snail infestations happen in this tank at the moment and it is impossible to kill them all without using chemical.

Aquarium video:

Description of the Area Surrounding the Biotope: Description of the area surrounding the biotope: Rio Negro is the largest left tributary of Amazon river and is the largest blackwater river in the world. It provides approximately 14% of the average annual discharge into the Amazon. Its basin is approximately 691,000 km2 in size.

Description of the Underwater Landscape of the Biotope: During the wet season, the abundant rainfall causes the forest to flood, leaving the trees submerged in water. The substrate in the area consists of white sand and is covered with fallen leaves and branches.

Description of the Habitat Parameters: The Rio Negro’s water is extremely low in mineral content, with conductivity of 8 µS. It has the color of strong tea and is extremely acidic with the pH around 2.9-4.2 due to the high concentrations of humic and tannic substances which come from the decomposition of organic matter. Water temperature during the low water season varies between 28-30°C.

List of Fishes and Invertebrates Occurring in the Nature Biotope: Paracheirodon axelrodi, Nannostomus unifasciatus, Nannostomus eques, Bryconops sp., Hemigrammus sp., Aequidens tetramerus, Dicrossus filamentosus, Apistogramma sp., Amblydoras sp., Hemigrammus belottii, Hemigrammus levis, Hemigrammus analis, Moenkhausia sp.

List of Plants Found in the Nature Biotope: Virola elongata, Eschweilera longipes, Pithecellobium amplissimum

Threats to the Ecology of the Biotope: The deforestation of the Amazon rainforest destroyed habitats, decreased biodiversity, resulted in soil erosion which pollutes river.

Sources of Information:
1. https://m.youtube.com/watch?v=2pqQaPrX1cY

2. https://en.m.wikipedia.org/wiki/Rio_Negro_(Amazon)

3. https://amazonaid.org/resources/about-the-amazon/effects-of-deforestation-on-the-amazon/

4. https://zookeys.pensoft.net/article/32055/

5. https://m.youtube.com/channel/UColBkR8Xp-3JceosHjxsVrg/featured

6. https://www.scielo.br/j/jbchs/a/wQyC6zfY6Vv4Bhftj6wdSxw/?format=pdf&lang=en

7. https://www.feow.org/ecoregions/details/314

8. https://www.amazonasmagazine.com/2017/01/09/biotope-video-blackwater-shallows-in-the-middle-rio-negro/

9. https://www.scielo.br/j/jbchs/a/frgjRVJCP5dvkV7CvYc7y3n/?lang=en

10. https://en.m.wikipedia.org/wiki/Igapó