Southern African Swamp Biotope Tank
The Okavango Delta is among the largest swamps in Africa. The waters support a variety of species and vigorous plant growth making it an ideal subject for a biotope aquarium. This delta is sometimes referred to as the Okavango Swamp and is situated in Botswana; it is also the world’s largest inland delta.
At one time it was a lake which dried up 10,000 years ago resulting in a river that has no outlet to the sea. Instead the water disperses over the Kalahari Desert and the actual delta is prone to flooding on an annual basis. As there is no industry or agriculture along the River Okavango the water is extremely pure without any pollution from commerce. Reedy plants line the shores of the waterways and shallow pools. Floating grasses and lilies are found where there is little current. Banks along moving waterways drop off quickly, creating cliff-like formations with overhanging roots. Many fish seek refuge under these root overhangs and inside caves.
The water tends to be alkaline with the pH ranging from 7.2- 7.8; hardness being soft to medium. Temperature wise it ranges from 21-24°C
Setting up the tank
The minimum recommended size tank is 100 liters (22gallons) but as in most cases the larger the better.
The substrate should be fine gravel or sand with hiding places added, these can be created from wood or even by using rock formations to create caves. Bright lighting should be used for most of the plants, but plants like Anubias may need to be planted in shady areas attached to the wood.
Water flow should be slow to medium but good filtration is required as the water needs to be crystal clear.
Plants for the tank
African water fern is ideal for decorating the wood in the back, it will grow quite tall when attached but can also be used as a floating plant if required. Marsilea (common name clover fern) makes a great foreground plant and given time will form a nice green carpet over the substrate.
Eleocharis (common name hair grass) will also be ideal for a background plant. It can grow up to 48 inches tall in its natural habitat but does require bright lighting
Anubias, as mentioned earlier, attached to wood will grow in lush green miniature bunches but shade it from the bright lighting.
Nymphea (tropical lily) is the best choice for a specimen plant, easy to grow but if too many surface leaves appear these can be pruned right back to allow for more growth under the water line.
Fish for the tank
African tetras, spiny eels, barbs, Hemichromis, Syndontis, and Clarias catfish will look well at home in this biotope.
If adding the spiny eels, be careful which species you purchase as some like the tire track can grow up to 36 inches in length; there are smaller species like the Macrognathus Aculeatus that grow to 14 inches in their natural habitat, but in an aquarium will rarely grow above 8 inches.