Southeast Asian Blackwater Pool
The creeks and streams that are located in the rainforest areas are often invisible from the air due to the dense coverage of vegetation but once found on foot they can be quite a size. As they are often found containing decaying vegetation on the floors of the rivers the water is very acidic and stained, this gives rise to the term Black Water.
Even with the very acidic conditions they still provide a home for many species of fish and plants. The pH will normally range from 5.5 - 6.5 and the water is extremely soft (0 - 4 DH is the normal hardness).
The temperature of the water is also higher than many other water filled areas ranging from 27 - 29°C.
Water movement is also very slow so this needs to be recreated in a biotope for this area.
Setting up the tank
As with most biotopes a tank of 100 liters (22 gallons) is fine, a more spectacular biotope will be created with a larger tank but the choice is yours. The substrate should be fine gravel or a clay substrate like laterite, a layer of both would definitely be beneficial to the plant life. Adding bogwood will aid keeping the water soft and acidic, plus it will provide plenty of hiding places for the fish.
As mentioned earlier, the water flow should be minimal, so slowing down the filter output will help, as will adding some peat medium to the filter to reduce the pH. Lighting does not need to be too bright, moderate lighting will be fine with the suggested plants for this biotope.
Plants for the tank
Eleocharis can be used for the foreground; this will propagate itself by means of runners, resulting in a lush, green carpet at the front of the tank. Nymphea is a tropical lily which will provide an excellent specimen plant selection, plus it will also provide some shady areas for the fish to hide in.
Cryptocoryne Affinis should provide some lush mid ground growth; this plant will grow up to 12 inches but does not demand bright lighting. Mixed in the foreground with the Eleocharis, add some Cryptocoryne Wendtii. This is commonly known as the tiny crypt and if planted in small clumps will stand out.
Fish for the tank
Gouramis have to be the first choice for this biotope. There are many species to choose from, one in particular stands out for me. This is the Paradise Fish (Macropodus Opercularis. This species comes in a variation of colors making each fish unique and they really stand out in the right aquarium. Another Gourami I am very fond of is the Pearl Gourami (Tricogaster Leerii) with its wonderful markings. Harlequin Rasboras, Glass catfish, and any of the danios will also make suitable tank inhabitants.
Loaches will also provide some entertainment within the tank, but please be aware some of the loach species can grow to quite a large size, so be prepared to upgrade to a larger tank if needed.
Sources of information
Taken from Rhett A. Butler/mongabay.com.