South American Blackwater Creek
Black water creeks originate from the rain forests, tributaries from the main rivers slow down into slow moving creeks that are stained a coffee color from the decaying vegetation and fauna. Often fallen trees are found in these creeks providing hiding places for the aquatic life who have adapted to living in these very acidic water conditions. The water will appear relatively transparent but once the seasonal rains take place the water takes on a very different complexion. The water becomes muddy as the rains sift down the silt from the surrounding lands areas, dragging in even more vegetation and tree branches with it. There is no hardness to the water which explains the very low pH and the creek beds are made up from a fine clay or sand. Rocks are very rare in Black water creeks, so much so that the local inhabitants use rocks for trading purposes.
The canopies above are quite dense, blocking out much of the sunlight, these are favorable conditions for the more timid fish species and amphibian life.
The creek beds are normally orangey color clay with a couple of inches of rotting vegetation on top. Flood water creates several ox-bow lakes to the sides of the creeks which in turn will have their own inhabitants, often fish swept over with the flood water.
There is plenty of insect life above and on the surrounding banks of the creeks for the fish to feed on, especially in the rainy season when food is at its most obtainable. This is the time that most of the fish species will go into spawning mode.
The pH of the water is found to be 5.5-6.5, hardness is very soft (0-4 DH), and the temperatures are higher than most tropical areas, running at 26-29°C.
Setting up the tank
To recreate this biotope it is a fairly easy task with a little imagination. Fine sand or clay needs to be used for the substrate, laterite would normally be suggested but as the plants to be added are limited in this set up then stick with the cheaper option. Create formations using wood, mopani us ideal as it will help to reduce the pH as well as adding tannins to the water to give the coffee colored effect. Be creative with the wood to create interesting shapes but don’t make it look too formal, random is better. Random planting with the suggested plants should also be random, try to cover areas of the wood to provide hiding places. Lighting needs to be subdued and the water flow from the filtration should be very low.
Plants for the tank
Sword plants and Vallisneria is all that is needed for this biotope as the wood arrangements are the main feature. Sword plants come in a variety of sizes according to the species, so include several different species in the tank and use the Vallisneria as a back ground to middle ground plant. Always plant randomly.
Fish for the tank
This biotope can either be a discus or angelfish biotope but do not mix them. For the more inexperienced fish keeper I would recommend going for the angelfish biotope as they are a much hardier species. Tetras, especially cardinal tetras look really stunning if added as a small shoal, and for the bottom feeders a group of Corydoras will keep the substrate clean.
Other fish that can be used are Hatchet fish, Loricarids and Dwarf cichlids. Apistogrammas will always provide entertainment in the tank.
Source of information
Taken from Rhett A. Butler/mongabay.com.