Lake Malawi is one of the Great Rift Valley lakes on the African continent, and just like the other Great Rift Valley lakes it is famous for its rich wild life. Aquarists appreciate the myriad of different cichlid species than can be found in Lake Malawi. Lake Malawi is a 40,000 year old lake and a lot of the cichlid species have developed in Lake Malawi and can be found nowhere else in the world. Lake Malawi is a large lake and contains several different environments: the rocky shores, the sandy bottom and the large open water areas. Malawi cichlids are found in all these environments and they have developed to fit into each niche. When you keep Malawi cichlids in your aquarium it is therefore important that you know which niche they inhabit in Lake Malawi, since different cichlids will appreciate different set ups.
Lake Malawi is 560 kilometers long and 75 kilometers wide at the widest point, which gives it a total surface area of almost 30,000 square kilometers. Three different countries share Lake Malawi: Malawi, Tanzania and Mozambique. Lake Malawi is therefore known under several different names, including Lake Nyasa, Lake Niassa and Lake Nyassa. The old European name for Lake Malawi is Livingstone’s Lake. Water enters Lake Malawi chiefly via the Ruhuhu and the Shire River is the major outlet.
Aquarists usually divide Malawi cichlids into two main groups: Mbuna cichlids and Peacock cichlids. Mbuna means rock-dweller in one of the local languages, and it is a very suitable name for these cichlids since they inhabit the shallow and rocky regions along the shores of Lake Malawi. Mbuna cichlids are also found around the shores of the islands in Lake Malawi. Mbuna cichlids will typically display a strong, pastel coloration. The male is more vividly colored than the female, but if you keep only female Mbuna cichlids in your aquarium the dominant female can start to display a more striking coloration. When two male Mbuna cichlids live near each other, the weakest one can dampen his colors and look more like a female in order to reduce aggression. You should never keep two male Mbuna cichlids in the same aquarium unless you have a very large aquarium where they each male can claim his own territory. It is important that create natural territorial borders when you decorate the aquarium and the males must be able to stay out of each others sight. Since Mbuna cichlids spend their lives among rocks, caves and crevices it comes as no surprise that they are cave breeders.
The Peacock cichlids are instead found in the open waters in Lake Malawi. In the wild, Mbuna cichlids and Peacock cichlids hardly ever meet each other and it is not advisable to house them in the same aquarium. The name Peacock is derived from the vibrant coloration displayed by the male Peacock cichlids. Female Peacock cichlids have a duller and more camouflaging coloration. Peacocks are often carnivores, but some of the species feed on zooplankton. Peacock cichlids are ovophile mouthbrooders, which means that they female Peacock cichlid will guard the eggs inside her mouth.
Water temperature should be 23-28oC (73-82oF), so a middle value of 25-26oC (77-79oF) is probably ideal. At the lower end of this scale, the fish may be less aggressive, but also less active and less inclined to breed. The general hardness in Lake Malawi is not as high as many might think – around 7 degrees GH. The carbonate hardness is around 10-12 degrees KH, which leads to the higher pH values measured – in the region of 7.8-8.6.
Therefore, in an aquarium setup, the GH should be 7 or higher and KH ideally around 10-12, although these values are not critical. pH is more important and should be maintained close to 8. Never allow the pH of a Malawi setup to fall below 7.0 and into the acidic range. If your tapwater or other source is already quite hard, you may only need to add a buffer to increase KH/pH. If your tapwater already has a higher KH/pH, then it is probably ideal for Malawi cichlids which will make things easier – it may also be a reason to consider these cichlids in itself, as it is generally much more difficult to lower the pH of aquarium water if you have hard alkaline water and wish to keep softwater fishes.
However, if you do not have hard, alkaline water, there are several ways in which you can increase either the GH, KH/pH (which are closely related), or both. There are various rocks (and substrates) which will help increase the hardness and pH of the water, and these include various forms of limestone rock (especially the crumbly tufa rock) and materials such as crushed shells or coral gravel, which can be placed in the filter.
There are also commercially available products designed to mimic to some extent the hardening and buffering salts found in these lakes. If your GH is too low, you can use one of the cichlid salts to boost the general hardness and mineral content to the desired level. Use at the initial tank setup and during subsequent water changes to maintain consistant hardness levels. After adjusting the general hardness, you may need to add one of the buffer products to achieve the desired KH and pH.
Note that if you have soft water, you must not use normal salt (sodium chloride) in an attempt to replicate appropriate water conditions. Common salt increases the overall mineral content of the water, but does not increase hardness or pH. So instead of making soft water into hard water, it merely makes soft, salty water – which would be most inappropriate for these cichlids. Table salt, cooking salt and most ‘aquarium’ salts are based on sodium chloride. Marine salt does increase hardness and pH, but is still not an appropriate composition for these freshwater fish.