Only fish from the coral reefs, for vivid colouration, perhaps rivals the endemic cichlids of Lake Malawi. Unlike marines, Malawi cichlids are more robust, and relatively easy to maintain and breed.
The word 'endemic' means 'occurring only in a specific location', which is most unusual in fish terms. Over many thousands of years, fish all over the world have spread through drainage systems, evolving as they went, into the many different species we know today (plus those we have yet to discover!) The unusual thing about Lake Malawi is its isolation, due to natural features like waterfalls, from any other drainage system. This has prevented the fish from entering any other river system, leaving us, the hobbyists, with a fantastic choice of fish that occur nowhere but in Lake Malawi.
Lake Malawi was formed along with the other Rift Lakes, approximately three million years ago. Rather ironically, I suppose, this happens to be the time when the first man-like creatures were also beginning to emerge in this area of East Africa. Lake Malawi is also a very large lake - it is, in fact, the ninth largest in the world, being 580 kilometres long, with a surface area of around 30,000 square kilometres, and depths in excess of 700 metres.
Now we have some background knowledge about why these cichlids are so special, and before we go on to setting up an aquarium for them, what should we as serious aquarists need to know about Lake Malawi? Of course, we must determine what water conditions prevail there. This, again, is an unusual feature of the African Rift Lakes, in that the water is extremely hard and very alkaline. Hardness values of 20°dH plus, together with a pH value of between 7.6 and 8.6 would be ideal.
Fortunately, it is easier to make soft water hard than vice versa, as those of you who followed my Discus series will be aware. If you have tap water of the wrong composition, what can you do about it?
Much of the literature available on Rift Lake Cichlids advocates the use of salt - Sodium Chloride (NaCl) to increase the hardness and pH. I would not agree with this advice, on the grounds that chlorides do not exist in the Lake's chemical make-up. Sodium Bicarbonate (NaHCO³) is another chemical often used to raise the pH in a Malawi tank. While I would accept a short-term rise in pH would take place, "Bicarb" has no lasting buffering effect.
TAP (Technical Aquatic Products Ltd.) have taken all these factors into consideration and have produced pH Alkaline Adjuster, a product of the right formulation to produce water eminently suitable for Rift Lake cichlids, while maintaining buffering capacity for pH stability. Please remember, when adjusting pH with fish present, you must do it slowly. The pH scale is logarithmic i.e. there is a tenfold difference between each value. Thus, pH6 is ten times greater than pH5; pH7 is one hundred times greater; pH8 is one thousand times greater. Large changes in pH should be made gradually over several hours, using an accurate test kit.
Enough of the technicalities for the moment. What about setting up the tank? A standard three-foot, all glass aquarium is an ideal size for your first Malawi community. What about filtration? For reasons I shall come to later, it is absolutely vital that an efficient biological filtration system is used. I have found the under gravel method to be ideal.
I personally prefer Rena U/G plates because of their versatility. The system can either be air or power head driven, although the latter is probably more efficient and infinitely quieter! As to the filter medium or substrate, you will already be aware that it would be beneficial to use a medium that assists in maintaining the hard, alkaline conditions required.
If you already have hard water from the tap, excellent results can be achieved with ordinary aquarium gravel. But if soft water prevails, and for a better aesthetic effect nothing really surpasses Calcium Plus to a depth of around 1½"-2" topped off with around 1" of coral sand. Separate the two with a Gravel Tidy. (If at this stage you have gone off the idea of Malawi cichlids, then with this filter configuration and a bag of marine salt......).
It is important to use a Gravel Tidy to prevent the two substrates mixing, and to stop the fish "digging" down to the U/G plates and rendering the filter useless. Water will take the least line of resistance through the "hole" in the filter bed.
Now is the time to provide the rocky environment that these fish prefer. Limestone or Tufa rock are ideal in these conditions and, of course, it is important to create as many caves and territories as possible. Please be absolutely sure that the foundation stones are down on the Gravel Tidy, as when the fish start to dig, collapse could otherwise ensue with predictably disastrous results!
Fill the tank with water and adjust the pH as discussed earlier. Temperatures should be maintained at around 25°C.
Earlier I mentioned that our tank must utilise a really effective filter. I shall now elaborate. To reduce violent combat in our aquarium, we must break from normal practice and crowd the fish.
A 36"x12"x15" tank should contain around twenty, three to four inch fish. This of course, means a massive amount of waste products (i.e. ammonia) that our filter must be able to cope with. Unfortunately ammonia (NH³) is lethal in an alkaline aquarium, as it occurs in its molecular state. In soft, acid water aquarium, the ionised form ammonium (NH4+) is present, which is relatively harmless.
The form which the ammonia is thus dependent on the prevailing pH, and will change along with it. This is a reversible reaction and is represented by the following equation: NH4+=NH³+H+. With this information in mind, it is obviously necessary to achieve maximum nitrifying bacteria colonisation of our filter media. It has been scientifically proven that by using a maturation agent, Like Establish (TAP), it is possible to have up to 300% more nitrifying bacteria present than if the tank were allowed to mature normally (organically).
Of course, by inducing the nitrogen cycle with 'Establish (TAP) there has to be a drawback. Patience must be exercised, as no fish can be kept in your tank until the nitrite (no²) level has peaked and fallen to zero, which can be monitored using an accurate test kit. This unfortunately takes about three to four weeks but the benefits to your filtration make the wait well worthwhile!
Once the tank is mature it is probably a good idea to put some Ammonia Remover (TAP) in a power filter. This is a naturally occurring ion-exchange resin, which will assist you with effective management of the nitrogen cycle. It will also be advisable to make a 20% to 25% water change every one to two weeks, which will not only help keep pollutants at bay but will also stimulate spawning.
At last it is time to make your fish selection. Basically, mouth brooding Malawi cichlids are split into two groups: the Utaka (the open water swimmers) and the Mbuna (or rock dwellers). It is not really advisable to mix the two. Mbuna are probably the group more suited to the set-up described above. Make your choices from members of the following genera: Pseudotropheus, Labeotropheus, Melanochromis or Labidochromis.
Whichever fish you decide upon, always try to purchase trios (one male and two females) where possible. This helps in two ways - it helps prevent polygamous males continuing to try to spawn with a female that already has a mouthful of eggs. And it minimises the risk of unnatural hybridisation, both between fish of the same genus but different colour morph, but (more importantly) between those of totally different genera. One has only to look at the pathetic examples of "Malawi's" that come from Singapore to realise why hybridisation should be avoided at all costs. This quite apart from the conservation aspects of the issue.
In the wild, Mbuna feed on the 'Aufwuch', which is the name given to the algal mat which covers the rocks in the Lake. They eat both the algae itself and the invertebrates contained therein. In captivity they adapt to the normal offerings, but it is wise to supplement with some form of vegetable, i.e. peas, lettuce, or spinach.
If you have adopted the methods so far described in this article, your charges will almost definitely spawn for you.
To reduce the possibility of stress, caused by further harassment from the male, it is better to net the female after about three days and transfer her to a small brooding tank with exactly the same water conditions as the community tank.
Change some of the water every day with that from the main tank. On her own in this way, the female will release the young from her mouth to feed after about three to four weeks.
The female has not herself eaten over this period, and so she should be isolated for a further one or two weeks to enable her to put on some weight.
Should you wish to introduce new fish into an established community, you must disrupt existing territories by moving around the rock work. In the confusion of claiming a new territory, the new fish will slip in unnoticed.
© Max Pickering 1999