South American Clearwater Stream Aquarium Biotope
Clear or blue water streams are the small transparent rivers that drain off the surplus water from the Guyana highlands and the rocky highlands of Brazil. The currents in these streams can vary from place to place, fast flowing currents in one area right down to slow moving waters further along. Two examples of these rivers are the Rio Xingu and the Rio Tocantins. As the streams head towards the sea the water is cascaded over a rocky floor, this in turn acts as a filter to remove any impurities that may be found present.
The pH of the water is found at 6.9 - 7.3 and the hardness of the water is soft to medium hardness (5 - 12 DH), temperature is normally within 24-28°C. The river beds are covered in fine white sand with small to medium sized stones scattered about and the banks are full of vegetation from the rain forest.
Setting up the tank
The recommended size tank for this biotope is 100 liters (22 gallons). To recreate the natural habitat fine white sand should be used but fine gravel is also used by some keepers. To keep the water crystal clear good filtration is a must. Bright lighting will show off this set up well alongside a good selection of plants. Medium sized stones placed on the substrate in a random fashion will give the tank a more natural look along with a couple of pieces of either driftwood or well soaked bogwood (mopani). Heavy planting to the rear will give the impression of fertile river banks and aeration to the tank will prove beneficial.
Plants for the tank
A general selection of plants can be used from the following species, sword plants, ceratophyllum, cabomba, lemma, limnobium, Vallisneria.
Keep the tall plants to the rear of the tank and use some of the miniature swords towards the middle ground and fore ground.
Species of fish for the tank
The armoured catfish make a good addition especially the bristle nose ancistrus as they will do a great job of keeping the tank free from algae, if you wish to spend a few extra pennies on a rarer catfish then the zebra plec is also ideal. The zebra plec is now protected and cannot be imported anymore but there are now quite a few breeders that have successfully raised fry, be prepared to pay a good price for them though.
Corydoras will also do well in this biotope, cleaning the substrate on a daily basis scavenging for food. If you are adding Corydoras it might be more advisable to use a sand substrate rather than fine gravel as their barbells can easily be damaged.
Dwarf pike cichlids should be chosen rather than the larger species as they can become aggressive and very territorial, the planting will provide some hiding places for the more nervous inhabitants but limit the numbers of these.
If using the smaller tank then many of the South American dwarf cichlids should feel well at home with this set up, the secret to keeping this biotope successful is to maintain a water flow with good filtration and regular water changes are a must.
Source: Rhett A. Butler/mongabay.com.