This Lake Tanganyika biotope aquarium uses Vallisneria spiralis (Italian Val) to aid in nitrate control. Vallisneria spiralis normally gets to be up to 36 inches (90 cm) long, but are kept short in this aquarium by Tropheus sp. cichlids that graze on the plant all day long.
Suitable substrate for Malawi and Tanganyika aquariums include, aragonite, dolomite, and calcite. You should not use any substrate that will add ammonia or nitrate to the system as they can bring the pH down.
Malawi fish prefer a pH between 7.8 and 8.6. Tanganyika fish prefer a pH between 8.6 and 9.4. For Malawi fish aquariums I normally aim for a pH of 8.3 to 8.4, and for Tanganyika fish I keep the pH between 8.6 and 8.8. The preferred pH buffer for raising and maintaining the pH this high is sodium carbonate. Sodium bicarbonate will not raise and keep the pH in these upper ranges.
For Lake Tanganyika fish you should have a alkalinity of around 330 ppm (18.48 dKH) and general hardness of 310 ppm (17.36 dGH). For Lake Malawi fish you should have a alkalinity of around 80 ppm (4.5 dKH) and general hardness of 86 ppm (4.8 dGH).
Guppies, mollies, swordtails, variatus, and platies are common livebearers that have been in the hobby very long time and have been developed into many different color strains. These livebearers all come from geographic areas that have limestone as a common rock. Limestone slowly erodes as rainwater flows over it, adding to the hardness and alkaline pH. Many species of mollies are often found near the sea, and in some cases they will venture into the sea. Typically livebearers are found in flowing bodies of water, but some population can be isolated in ponds or lakes.
In the aquarium livebearers do very well in planted aquariums. Plants help provide cover for newly born fry. In an aquarium that lacks predators, livebearers population can become very dense. Many species of livebearers have a short lifespan, on average living only one or two years. To keep a self sustaining population going, filter intakes should have a sponge or nylon netting placed over the intake to prevent fry from being suck into an impeller.
Guppies, platies, and variatus can be kept in aquariums as small as 5 gallons (19 l). Swordtails should have a 20 gallon or larger aquarium. Some species of mollies should have a 50 gallon or larger aquarium. Sailfin mollies (Poecilia latipinna), Poecilia velifera and Poecilia petenensis (a.k.a. Yucatan molly) can grow between 4 to 6 inches (10 to 15 cm) and sometimes can become combative.