Torrents and streams

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photo d'un paysage de rivière
Rivière avec rapide dans le nord est de la Thaïlande
© Frederic Fasquel

What is a torrent? And a stream?

Torrents and streams encompass what are referred to as fast-moving waters. Water flow is turbulent, fast and generally tends to slow down when descending in altitude towards hilly areas lower down. This distinction from rivers is arbitrary but enables waterways to be classified into two families, presenting very different hydrologic and biological conditions.

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Rivière forestière dans l'est de la Thailande
Rivière forestière dans l'Est de la Thaïlande
© Frederic Fasquel

The water in streams and torrents comes from surface rainwater flow and springs. It tends to be clear, well oxygenated due to the turbulence caused by waterfalls and rocks, fresh and quite acidic. Their beds consist in slabs, rocks and pebbles that can stand up to the strong currents.

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Bac de rivière rapide d'Asie à l'Aquarium tropical
Bac de rivière rapide d'Asie à l'Aquarium tropical
© Frédéric Fasquel
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Sous la surface d'un petit torrent avec des gobies
Sous la surface d'un petit torrent avec des gobies
© Frédéric Fasquel

Which species can be found there?

In order to live in these turbulent waters, fish must be good swimmers and capable of sticking close to the rocks to avoid being swept away. This would include fish from the loriicaridae family, such as the Ancistrus or Plecostomus, and also Borneo loaches. Certain migratory species swim up rivers to reach these streams where they breed.

For example, the Channa andrao swims up the Brahmaputra river to go and breed in the Sankosh- Raidak rivers.

Ecosystems

The main aquatic environments presented at the Aquarium