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Rift Valley Cichlids, part 2: Marvellous Malawi
Last time we looked at Lake Tanganyika, the largest of the African Rift Valley lakes. While Lake Malawi is a little smaller than Lake Tanganyika, it is home to several times more species of cichlid. Current estimates put the number of cichlids in Lake Malawi at around 650 species, compared with around 200 in Lake Tanganyika. From among these hundreds of species come some of the most colourful and vivacious fishes in the hobby, comparable to anything found in a saltwater aquarium.
Of course, being freshwater rather than marine fish, Malawian cichlids are that much easier to look after, and in general have proven to be robust and easy to keep. Their bright colours have made them a favourite choice for aquarium designers furnishing offices and restaurants, often created freshwater reef tanks by mixing Malawian cichlids with artificial corals and seashells.
The Malawian cichlids: Mbuna
The cichlids of Lake Malawi are predominantly members of the subfamily Haplochrominae, colloquially known as the haplochromines or haps. Of these, a large proportion belong to a group known as the mbuna, including such important genera as Labeotropheus, Labidochromis, Maylandia, Melanochromis and Pseudotropheus. The name “mbuna” itself means “rockfish” in the language of the local Tonga people of Malawi. This is a reference to the fact these fish are associated with rocky reefs and shorelines. Mbuna graze on the aufwuchs (a mix of algae and other micro-organisms) that encrust the rocks using modified jaws and teeth. When alarmed, they dive into the rocks for safety.
Mbuna are relatively small cichlids, typically between 8 and 15 cm in length, adapted to life close to rocky shorelines and reefs. They are all maternal mouthbrooders, and often sexually dimorphic. In some cases this dimorphism is relatively slight, as in the case with Maylandia zebra (formerly known as Pseudotropheus zebra) where both sexes have the same basic colouration but the male has several yellow spots on his anal fin. The female either has only a few of these or none at all. During breeding, the female pecks at the anal fin after she has gathered up her eggs, and the male then expels his sperm, fertilising the eggs in her mouth.
Because it has been supposed that she pecks at the yellow spots on the anal fin mistaking them for eggs, these spots are sometimes called “egg dummies” or “eggspots”, though whether the female really is deceived into thinking the spots are eggs has been disputed by many scientists. Studies of Labeotropheus has revealed that dominant males have more of these yellow spots than non-dominant males, so females could use these markings to deduce which males would make the best mates. Males could also use the spots to decide whether or not fighting a rival male is worthwhile, by assessing its position in the hierarchy beforehand.
Bright yellow spots on the anal fin also make males more visible to predators. Any male that manages to reach sexual maturity despite having lots of bright yellow spots on his anal fin is clearly a healthy, alert, and fast-moving fish: prime genetic material for the female to acquire for her offspring. Evidence for this interpretation comes from the fact that females prefer males with more and brighter eggspots, and also the observation that cichlids in clear or shallow water habitats tend to have smaller eggspots than those in murkier or deeper environments. Presumably a balance needs to be struck between eggspots that are bright enough to exert some selection pressure in favour of fitter males, but not to the degree that the males are so obvious that predators can eat them all.
Mbuna tend to be very aggressive, though this varies somewhat depending on the species. So while extremely colourful and great fun to keep, they generally work best in their own aquarium away from other Malawian cichlids. This also helps at feeding time: most mbuna need to be given a greens-based diet rich in algae, spinach, tinned peas, and other such foods. When fed too much meat, they tend to become unhealthy and prone to “Malawi Bloat”, a dropsy-like disease that is very difficult to treat.
The Malawian cichlids: Everything else
Closely related to the mbuna are the peacock cichlids of the genus Aulonocara. Unlike the mbuna, peacock cichlids are predators, feeding primarily on small invertebrates such as insect larvae and crustaceans. There are a great variety of species, many of which are brilliantly coloured. Most are around 10-15 cm in length. While they are territorial, they are less aggressive than the mbuna, and can make excellent community tank residents. Peacock cichlids are maternal mouthbrooders.
Another group of haplochromines kept in aquaria are the utaka. This group contains the genera Copadichromis and Mchenga. They are medium-sized fish around 15 to 20 cm long that live in open water, often some distance away from the substrate. Males maintain territories while females move about in small groups. Again, these cichlids are maternal mouthbrooders.
The mcheni are the large (up to 50 cm) predatory cichlids of the genus Rhamphochromis. They feed extensively on small fishes, particularly the lake sardine Engraulicypris sardella that, despite its name, is actually a type of barb. Mcheni are superficially very barracuda-like in shape and habits. Despite their large size and predatory habits, these cichlids are rather peaceful and do not mix well with more aggressive cichlids. They are maternal mouthbrooders.
The final major group of cichlids are known as chambo. These are tilapias of the genus Oreochromis. They open water fish that feed on algae, zooplankton, and organic detritus. Being rather large (around 30 cm) and good to eat, they are more important as food fish than aquarium fish, and are not routinely offered to aquarists. In common with other members of the genus, they are maternal mouthbrooders.
In broad terms, what holds for Lake Tanganyika holds for Lake Malawi too, so everything said in the earlier article in this series can be applied successfully to a tank containing Malawian cichlids. In general, the water needs to be hard and alkaline. The lake itself has a pH between 7.8-8.5 and a carbonate hardness around 6-10 degrees KH. Water chemistry fluctuations must be avoided. Water quality is also important, and a good filter system is essential since these fish are active and often greedy feeders. Regular water changes of at least 50% per week are recommended.
Decorating the Malawian tank
Again, what went for the Tanganyikan tank largely goes for the Malawian tank as well. The main difference is that the mbuna especially require lots of rockwork. Most species will not stray far from cover, and many will fight vigourously over the choicest hidey-holes. So you will need to use a lot of rock to create the right habitat for them, and the rockwork will need to cover most of the back of the tank, almost to the top of the water.
Obviously creating such a tall and heavy structure requires some planning. Silicone sealant can be used to hold chunks of tufa or lava rock together to prevent them from tumbling down and damaging the tank. Tufa rock and lava rock make better choices than limestone boulders because they are not so heavy and generally fit together in such a way that there are lots more of the nooks and crannies the cichlids enjoy. After all, it isn’t the rocks the cichlids care about so much as the places the rocks allow them to forage and to hide.
Coral sand is often used in Malawian cichlid tanks and can work well, but it isn’t the only choice. Plain river or silver sand works well and isn’t so brightly coloured, and this encourages the cichlids to show better colours. Dark volcanic or black sand is even better. If all else fails, regular gravel will work well too.
The one thing to avoid is bogwood, at least in large quantities. While the fish will happily swim in and around bogwood roots, wood does tend to acidify the water over time, and this isn’t desirable in the Lake Malawi aquarium.
The cichlids of Lake Malawi tend to be aggressive and territorial. There are two ways to handle this. One approach is to understock the aquarium, and ensure that there is only one male with a harem of females. This system also allows you to maintain good water quality.
The other approach is to overstock the tank, using sheer numbers to prevent any one fish from being bullied too much. Without being able to secure a territory, the males becomes less aggressive. The downside is of course that an overstocked tank is difficult to maintain, and the aquarist needs to work very hard to ensure good water quality and avoid disease.
Whether under- or overstocked, Lake Malawi tanks need to be relatively large. A 200 litre aquarium should be viewed as the absolute minimum for a community tank, and even a lightly stocked single species tank containing a harem of one male and a few females won’t work if it is very much smaller than that. For the aquarist wanting to keep a large variety of Malawi cichlids, big tanks, 300 litres upwards, are essential.
Community tanks pose some additional problems beyond space requirements. Many Malawi cichlids will hybridise readily, and the resulting offspring are of no value to either aquarists or retailers. Indeed, many aquarists will only buy wild-caught Malawi cichlids to avoid ending up with hybrid stock unwittingly dumped on retailers by local breeders.
The other big problem with community tanks is that not all species are equally aggressive. Mbuna in particular tend to be more aggressive than peacock cichlids and utaka, so mixing these together isn’t a good idea. Even within the mbuna, there is a definite hierarchy in terms of aggression. At one end of the scale, Iodotropheus and Labidochromis tend to be relatively mild and easy to accommodate in a community tank, but at the other extreme many Melanochromis and Maylandia tend to be so aggressive that they will kill weaker fish kept with them. As a rule, fish are most aggressive to members of their own species and other members of their genus. Combining two male Maylandia zebra for example, or males from two different species of Maylandia, is asking for trouble.
To avoid problems with aggression and hybridisation, it is almost always best to choose only one species per genus, and then to stick with species of roughly comparable levels of aggression and territoriality. It is therefore very important to read up on the subject so that you can identify the fish on sale to species level and have a fair idea of its level of aggression and territoriality. Buying the wrong fish can be disastrous, both in terms of dead fish and wasted money. There are many good books on Malawi cichlids thanks to their enormous popularity, and reading one of these before getting any fish should be seen as an essential step in the process.
Picking out a few popular Malawi cichlids is difficult because there are so many lovely species available, many of which are regular fixtures in all but the smallest aquarium shops. The following are consequently just a taster.
This is medium-sized peacock cichlid that gets to about 10 cm in length, the females tending to be a little smaller than the males. Colours are variable but always impressive. Males in breeding condition have lemon-yellow bodies with blue around the face and throat and a few vertical blue bands on the flanks. Females are rather drab brown with grey vertical bands on the flanks. There are numerous regional varieties available. This species tends to be fairly good in community tanks compared with other members of the genus, and makes an excellent peacock cichlid for beginners.
This plankton-eating mbuna is available in lots of regional varieties. In the standard variety, the males are brilliant blue with dark blue vertical bands and a few yellow eggspots on the anal fin. Females are paler shades of blue. A popular variety collected from Nkhata Bay has a bright yellow dorsal fin. Males are rather aggressive and highly territorial, but their modest size (around 10 cm) makes them a good choice for robust community tanks alongside things like Maylandia zebra and Labeotropheus fuelleborni.
This is the famous Malawi blue dolphin, and one of the most impressive of all the Malawian cichlids commonly traded. While territorial, it isn’t especially aggressive despite its large (20 cm) adult size. Colouration varies depending on which variety is being kept, but most are bright blue with vague dark blue bands on the flanks. Adult males develop a huge nuchal hump that does indeed make them look a lot like dolphins. Females lack this hump and also tend to be quite a bit smaller. Cyrtocara moori have a peculiar feeding mode in the wild. They follow substrate-sifting cichlids about, snatching up scraps of food that are thrown up into the water. In the wild they are completely opportunistic and will eat just about anything. An excellent species for the community aquarium, but given its size, only suitable for the largest of tanks.
A relatively easy-going mbuna and one of the very best species for the beginner. It is quite small, no more than 9 cm in length, and provided the tank isn’t too small, groups of males and females will coexist happily enough. It also has a more catholic diet than most mbuna, eating not just algae but also small invertebrates as well. In the aquarium it will eat just about anything. The only downside to this species is its lack of brilliant colours, tending to be a rusty-red in colour with a purple sheen, making for a handsome rather than spectacular fish. Because it is so mellow, it should never be mixed with more aggressive cichlids.
A moderately aggressive algae-eating mbuna available in dozens of regional varieties sporting differences in colour. Typically adult males are blue whereas females are orange. An orange-blotch form, where the female is orange with black blotches, is especially popular with aquarists. Although wild fish rarely exceed 12 cm in length, in captivity this fish routinely gets quite a bit bigger, up to 15 cm being common. Males are pushy and tend to harass the females, and under some circumstances become “hyperdominant” bullying everything else in the aquarium as well.
This fairly placid omnivorous mbuna naturally occurs in a variety of colour forms, but it is the bright yellow variety that is most widely traded. Sexual dimorphism is not strong, particularly so given that unlike most other mbuna, eggspots are not seen on the anal fin of this species. Males tend to be bigger and the black streak along the dorsal fin turns blue when they are in breeding condition. Maximum size is around 10 cm in the wild, but sometimes a little more in the aquarium. Usually a reliable good community species provided it is not mixed with very aggressive species such as Melanochromis spp. that might harm it.
Possibly the most popular mbuna in the hobby, Maylandia zebra, formerly known as Pseudotropheus zebra, is generally easy to obtain in a wide range of varieties. It is a strict herbivore in the wild, and when fed too much processed or meaty food tends to bloat and become sickly. Males are extremely belligerent, and can become hyperdominant. They also tend to bully females that are brooding eggs. Mix only with robust cichlids, such as Labeotropheus and Melanochromis spp. Avoid mixing with other Maylandia or Pseudotropheus because of the risk of hybridisation. Because they are so outgoing and alert, these cichlids are highly entertaining. A lot of hybrid “African cichlids” are sold as Maylandia zebra, so it pays to shop around and look for wild-caught or properly identified stock.
A highly aggressive but extremely beautiful mbuna. This species is famed for its strongly dimorphic colouration. Females and quiescent males are yellow with a few longitudinal black stripes, whereas territorial males are almost completely black with a few yellow stripes. Maximum size is around 11 cm, with the males a bit bigger than the females. Because they are so pushy this species is best kept with species of similar aggressiveness and at least slightly larger size. They can and will kill milder tankmates unable to defend themselves.
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