Malawi Mbuna
by Andy Gordon of England, and Michelle Stuart of
Ontario Canada
Reprinted, with permission, from their web site Fishtanksandponds.net
Aquarticles
Mixed mbuna
Photo by Andy Gordon
The first thing to consider is what type of fish do you want to keep. Lake Malawi is so
big that it offers many types of habitat and each niche is filled with its own type of
fish. The most popular of these are the Mbuna, because of their bright colours
The Lake
Lake Malawi is the third largest lake in Africa and the ninth largest in the world. It
used to be called Lake Nyassa, and it is surrounded by three countries - Tanzania,
Mozambique and Malawi. It is almost 375 miles long and has a maximum width of 50 miles. It
has a depth of 700m in places but the average depth is 292m. The average pH is 7.8 to 8.6,
but surprisingly the GH is 4 to 6 and the KH is 6 to 8, making the water very soft. The
temperature at the surface varies from 23 to 28C. Because of the size and the huge volume
of water involved the lake is very stable, and the fish that live there have become
accustomed to this and generally they need to be kept in a stable environment if they are
to thrive.
The lake has over 600 known species of cichlid, many of them endemic to Lake Malawi
(which means they are found nowhere else). There are many habitats, from boulder strewn
shores to open sandy areas, Vallisineria beds to deep open water. The fish, known
locally as 'mbuna' (rock dwellers), are extremely colourful and are highly prized by
aquarists. Some of them can rival marine fish for colour. They are all mouth-brooders,
which means that they keep their eggs and young fry in their mouth until the fry are big
enough to care for themselves. They are also very aggressive, but this can be overcome by
correct care.
Tank
The tank should be the biggest possible. This is because it will be easier to maintain
stable conditions and it will give the fish enough room to escape a bully. The smallest
size you should consider is a 48" x 15" x 15", and in such a tank you would
have to limit your choice of fish to the more gentle less aggressive species.
Filtration
A good powerful external power filter is the best option for mainly biological and
mechanical filtration. Under-gravel filters are not much use because these fish constantly
dig and would short circuit the filter. These fish demand clean high quality water
conditions. Ammonia and Nitrite should both be 0, and Nitrate must be kept below 20 ppm.
This means routine water changes are essential. With mbuna there is a lot less aggression
when the fish are kept slightly crowded, which in turn means that any filter should be big
enough to cope with the higher than usual demand.
Substrate and decor
The substrate should not be too deep or it will trap dirt and adversely affect the water
quality. 1/2" is plenty and it should include some coral sand which will act as
a buffer and help to maintain the correct pH. Other open water species prefer sand
which they will sift through looking for food. Mbuna must have LOTS of rockwork in their
aquarium but open water species don't need any rockwork. If you use rocks in the tank make
certain they are stacked safely. Use aquarium grade epoxy resin to bond the rocks together
and put the rocks in place before adding the substrate, so that the fish can't undermine
them. All types of rocks can be used, including calcareous rocks - these will in fact be
useful since they will help buffer the water and keep it stable.
Water Chemistry
These fish have evolved in a very specialised way to be fully at home in a certain set of
conditions over tens of thousands of years. Whilst some of the captive bred fish have
become more tolerant of a wider set of conditions they are still at their best when kept
in the conditions they have evolved to best cope with. The water in Lake Malawi is hard
and alkaline, and whilst the hardness isn't critical the alkalinity is. They need a high
pH: 7.5 to 8.4.
Feeding
All mbuna will do very well on a herbivore diet with occasional live or frozen food added.
In the wild they graze on algae and any small creatures that live amongst it. This has
become widely known as Aufwuchs. In order to replicate this they need a light high fibre
diet. Suitable foods include Spirulina flake, vegetarian flake, daphnia, algae, thinly
sliced cucumber, lettuce, cyclops, daphnia and bloodworms. They should be fed little and
often, 2 or 3 times per day
Note: It is important not to rely too heavily on dried food because this has
been linked to a condition known as Malawi bloat, which as the name suggests causes the
fishes' bodies to swell and can result in death. Also, these are greedy competitive fish
with a strong tendency to over-eat, which results in obesity. Fish that become obese will
have shorter lives as a result.
The Fish
When selecting the fish for your tank there are some general rules which will help keep
things go smoothly. Keep only one adult male of each species with two or more females.
Don't keep very similar or closely related species together. The stocking level is
absolutely critical - if there are too few fish there is a very real chance of one of the
larger males becoming hyper-dominant and attacking all the other fish to the point of
actually killing them. Too many fish will lead to stress from over-crowding, which in turn
will lead to ill health. In between these two scenarios is the ideal, where there are too
many other males for a single fish to risk trying to become dominant but there is still
enough space to allow them to feel settled. This is what to aim for. Generally if you
allow one inch of fish for every eight sq. inches of water surface you will be in the
right area for the stocking level. But that is only a guideline - it will depend on the
individual set-up and fish concerned. Personalities even vary from fish to fish, so it may
be necessary to intervene at some point until you finally reach a peaceful tank. Under no
circumstances should you try to keep or breed these fish in a breeding tank using a single
male and female. This will nearly always result in the female's death.
Two male Melanochromis auratus deciding their rank. Photo
by Andy Gordon
This is only a very limited selection as there are some 600 known species and most of
those have a variety of morphs:
Iodotropheus, one of the more peaceful species.
Labeotropheus, keep only one male per tank.
Labidochromis, also generally peaceful (for mbuna).
Metriaclima, an offshoot from pseudotropheus.
Melanochromis, very aggressive.
Pseudotropheus, aggression varies from species to species.
Breeding mbuna
If these fish are kept in good conditions and free from stress they will breed very freely
in the community aquarium. Most species are extremely prolific, and good healthy colourful
young are very much in demand. What is more, the fry are very easy to raise. Having said
all that, I imagine you might be wondering why these fish are listed as being more
demanding to breed and not in the easy section. The reason is that they need a specialist
set-up in order to keep them, and they cannot be kept with other fish due to their special
requirements.
Selecting the parents
The fish will choose their own mates. To ensure good quality fry keep good quality stock.
There should be a ratio of one male to two females, and for the more aggressive species
one male to four or five females. Only one male per species should be kept per tank and
even similar looking species are best kept apart. Sometimes hybrids occur - if this
happens they must not be passed on or sold, because such action would eventually ruin the
captive bloodlines of these fish to everyone’s detriment.
Preparing
Maintaining healthy well-fed fish is all the preparation that is needed. The males are
constantly on the lookout for a female that is ready to breed. The males will hold a small
territory, and they will display vigorously to any passing female. If the female is ready
to breed, the pair will circle each other and the eggs will be laid. As this happens the
female will collect up all the eggs and hold them in her mouth in order to protect them.
A brooding female
Photo by Andy
Gordon
During this time she will not eat and she will lose some condition. The brooding
females are easy to spot because they tend to be thin and the brood pouch can easily be
seen in the region of the fish's chin. The eggs and fry will be protected in this way for
about one month. Once the fish have bred, wait for a few days to allow the female to bond
with the eggs and then transfer her to another aquarium with the same water chemistry and
temp. so that she can be on her own. The tank will need a mature sponge filter and some
stones with a little cave so that the female will feel secure. Don't offer any food during
this time, particularly with inexperienced fish, or the eggs and fry could be put at risk.
When the fry are old enough they will be released, and in most cases that is the end of
being protected. The mother should now be removed from the tank or there is a risk the fry
could be eaten.
Even if left in the main tank, some fry will grow up provided that
there are plenty of nooks and crannies to hide in, as this one inch Melanochromis
auratus shows.
Photo by Andy Gordon
Rearing
This presents no problems. The fry will eat finely powdered flake food and newly hatched
brine shrimp. They will also browse on the surface of the sponge filter and on any algae
present. After two weeks you can begin to make small daily water changes and gradually
increase the amount until after five weeks about 20% daily is being changed. These water
changes are every bit as important as feeding as far as the fry’s progress is
concerned. After ten to twelve weeks the fry will be ready to sell on at just over one
inch.
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