South American Whitewater River Aquarium Biotope
White Water Rivers have a muddy brown color with little visibility because of the heavy sediment content. In the main river, there are almost no plants and mostly large fish unsuitable for the aquarium. Quiet back water areas like the oxbow lakes have more aquarium fish species and greater plant life. White Water Rivers include the Amazon, the Napo, and the Orinoco.
The Amazon is the largest river in the world if measured by water volume and has the greatest water flow into the ocean; this has led to its nickname of the River Sea.
It is however only the second longest river in the world, the Nile being the longest. One of its most famous inhabitants has to be the Boto (Amazon River Dolphin) alongside the infamous piranha fish.
The waters of these rivers are generally soft to medium hardness 3-8 DH, with a pH of 6.8-7.1. Temperatures range from 26-29°C.
Setting up the tank
The recommended size of tank for this set up is 150 liters (33 gallons) which is slightly larger than some biotopes but the important thing is length of the tank rather then depth unless you wish to add angelfish.
Fine gravel or clay should be used for the substrate with varying pieces of either driftwood or bogwood added randomly for furnishings. Open swimming areas must be included so try to keep the decoration to the rear of the tank. If you are creating an ox bow biotope add some floating plants for a realistic effect.
Plants for the tank
Vallisneria will make a good background plant with its long slender leaves. This plant propagates by runners, once it is well established it will need regular pruning to keep it in check.
Riccia Flutens, commonly known as Crystalwort, is classed as a floating plant. The best way of using it though is to attach to the wood and let it spread over to form a coating of green, this is also another plant that will need lots of pruning once it takes hold, but the display it produces makes it worth all of the extra effort.
Sword plants are a must with all of the South American biotopes in my opinion, mixing the various species will produce an even greater effect.
For the floating plants, either water lettuce or duckweed can be used, if they start to smother the surface it is easy to siphon areas off to reveal clear spots to allow the light through.
Fish for the tank
There is a large scope with this biotope for selection of fish species to use. If your tank is large enough Acaras will feel well at home. Eartheaters and angel fish can also be used, Oscars are from this area but if you add them they will probably try to rearrange the tank décor. For shoaling fish add some Tetras and Hatchet fish, I always find that cardinal tetras seem to work best in a shoal but these can be a bit more expensive than the other Tetras.
For substrate cleaners use Corydoras, they will do a great job scavenging for food, but don’t forget that they also have their own dietary needs.
For a species only biotope there can only be one choice for me, a group of piranhas will give your tank that extra special look.
Sources of information
Rhett A. Butler/mongabay.com,wikipedia.