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Rift Valley Cichlids, part 1: Talking Tanganyikan
The cichlids of Lakes Malawi and Tanganyika have become among the most popular of all the fishes in the aquarium hobby thanks to their brilliant colours and dazzling variety. While some are demanding fish best suited to advanced hobbyists, others are hardy enough to do well even when kept by relatively inexperienced or casual hobbyists. Best of all, Malawian and Tanganyikan cichlids require hard and alkaline water conditions to do well, so the hard and alkaline water the average hobbyist in England is supplied with suits them down to the ground!
Of the two lakes, Malawi is slightly smaller than Tanganyika, but both are almost incomprehensibly vast bodies of water. At 30,000 and 32,000 square kilometres, each is about one and half times the size of Wales. Lake Malawi is about 560 km long and Lake Tanganyika about 670 km long. To put this into some sort of context, the distance from London to Edinburgh is about 644 km. Both lakes are deep, the average depth of Lake Malawi being around 300 m and Lake Tanganyika 570 m. At its deepest point, Lake Tanganyika is almost 1500 m deep; by contrast, the summit of Ben Nevis is a mere 1344 m above sea level.
These facts should make it clear that both bodies of water are more like small seas than lakes, and it is because of this that they support such an incredibly variety of endemic species. As well as the cichlids for which the lakes are famous, they are also home to a variety of other aquatic animals including catfish, spiny eels, crabs, snails, even jellyfish.
The Tanganyikan cichlids
For the first part of this series, we’ll look at the cichlids of Lake Tanganyika. In some ways they’re easier to keep than their Malawian cousins, being generally less aggressive (though still territorial) and consequently easier to combine in a community. There is also a nice variety of dwarf species too, and setting up an small single-species aquarium for these cichlids can be very rewarding. On the other hand Tanganyikan cichlids have a well-earned reputation for being sensitive to poor water quality, so anyone keeping these fishes will need to provide ample filtration and regular water changes.
The cichlids of Lake Tanganyika are typically assigned to one of twelve tribes. Of these, only a few are significant in the aquarium hobby: the Cyprichromini, Ectodini, Eretmodini, Lamprologini, and Tropheini.
The Cyprichromini are sometimes known as the sardine cichlids, a good name given their lifestyle. These are open water fish that live in large schools and eat plankton. There are two genera in this tribe, Cyprichromis and Paracyprichromis, species of which are reasonably commonly traded. They are all mouthbrooders.
The tribe Ectodini contains a number of genera typically associated with the substrate and in many cases sand-sifters that forage for prey in a way analogous to the earth-eating cichlids of South America. Members of this tribe are not common in the hobby, though some, including various species of Cyathopharynx and Xenotilapia, are periodically traded. All are mouthbrooders.
The clown and goby cichlids of the tribe Eretmodini are small, benthic fish that feed extensively on algae. Eretmodus cyanostictus is probably the most regularly traded, though other species in the genera Spathodus and Tanganicodus are sometimes seen as well. Eretmodine cichlids are mouthbrooders.
The tribe Lamprologini dominates the Tanganyikan cichlid trade, with numerous genera routinely represented in hobbyists’ tanks, including Altolamprologus, Julidochromis, Lamprologus, and Neolamprologus. Lamprologine cichlids are egg-layers.
The tribe Tropheini contains several genera with one in particular, Tropheus, being regularly traded and containing several very popular species. One of the biggest Tanganyikan cichlids, Cyphotilapia frontosa, is also a member of this tribe. These cichlids are all mouthbrooders.
The water in Lake Tanganyika is consistently alkaline (around pH 9) and very hard (around 12-14 degrees KH) and replicating these conditions in the aquarium is important. In practise though, most Tanganyikan cichlids have proven to be relatively adaptable, and what appears to matter most is not the precise pH or hardness values (provided they are not too from the ideals given above) but that the water chemistry in the aquarium should not change much over time. In other words, the water needs to be well buffered, and water changes should be small and frequent rather than large and occasional.
One approach is to use a pre-packaged Lake Tanganyika salt mix in the same way as marine salt mix is used to make up artificial seawater. An alternative approach is to rely on chemical filtration to harden the water and raise the pH. A good system is to combine a canister filter (for mechanical and biological filtration) with an undergravel filter (for chemical filtration). The outflow of the canister filter passes water into the undergravel filter plate, and as the water rises out of the plate is passes through layers of crushed coral and coral sand. In hard water areas of Britain, the water may be sufficiently hard and alkaline that chemical filtration is redundant, and simply by performing regular water changes and background changes in pH can be avoided.
While Tanganyikan cichlids are fairly adaptable in terms of water chemistry, what they won’t forgive is failure to maintain good water quality. These fishes are notably intolerant of nitrate, far more so than most other freshwater fish. The key things to avoid are overstocking, overfeeding, and insufficient water changes. As a general rule, you want to aim for a nitrate level of no more than 20 mg/l.
Decorating the Tanganyikan tank
Tanganyikan cichlids are well served with a tank containing plenty of rockwork for hiding in, some open sandy areas for foraging, and, in the case of the shell-dwellers, some empty shells for spawning in. The traditional Tanganyikan cichlid aquarium uses tufa rock for the rockwork, coral sand for the substrate, and empty apple or edible snail shells for the shell-dwellers.
Plants aren’t a major part of the Lake Tanganyika environment except around the mouths of the rivers the empty into the lake. There, plants like Vallisneria and Potamogeton can be found in abundance. While there’s no reason not to add plants tolerant of hard water conditions to a Tanganyikan aquarium, a lot of cichlids will either view them as food or else destroy them while foraging or landscaping their territories. Epiphytic plants, like Anubias and Java fern, are likely to be easier to accommodate in the aquarium that species that require a deep and largely undisturbed substrate.
While some Tanganyikan cichlids schooling fish that exhibit little aggression or territoriality, this isn’t true for most species and the aquarist must take care that each individual or pair has enough space to satisfy its territorial needs. Many are also aggressive towards any other species of similar shape and size. For that reason, it’s often best to include only a single species per genus. This minimises the chances of cross species aggression.
While Malawian cichlids, especially mbuna, are outgoing and easy to tame, Tanganyikan cichlids tend to be rather shy and often nervous. An aquarium well provided with hiding places will encourage them to settle down, but even then these are fishes that get on with their own lives rather than spend all their time begging for food. If you want robust, friendly cichlids then Tanganyikans are generally not a good choice. But if you enjoy watching the more natural aspects of cichlid behaviour, the Tanganyikans can be very rewarding.
The variety of Tanganyikan cichlids on the market is enormous, but the following are a selection of species that are easily obtained, known to do well in home aquaria, and generally peaceful enough to coexist in a community tank alongside species of similar size and temperament.
This laterally compressed cichlid feeds on invertebrates and small fish in the wild, but in the cichlid community tank it poses no threat to tankmates larger than guppies. Live and frozen foods of all types are accepted, though a mix of bloodworms, brine shrimps, and the occasional small earthworm works well. These are very mild cichlids and their tankmates need to be similarly gentle. This is especially critical at feeding time, when these slow feeders can easily lose out to more boisterous tankmates. Several varieties are available, collected from different parts of the lake. Maximum size is 15 cm for males and 10 cm for females. Sexual dimorphism is obvious even with immature fish, the males having a more robust head and larger fins. They do best in harems, with one male being kept with a group of females.
Similar to Altolamprologus calvus in shape and behaviour, this is another relatively placid cichlid that works well in quiet communities. Compared with Altolamprologus calvus, this species is more deep bodied but with a shorter snout. As with Altolamprologus calvus, there are many varieties of Altolamprologus compressiceps available in the trade.
The ‘frontosa’ is one of the most popular and easy to keep Tanganyikan cichlids, suffering in only one regard: size. Adults are 30-40 cm in length, with males being slightly larger on average than the females. Obviously such big fish require a massive aquarium, upwards of 700 litres. On the other hand, these are spectacular fish with brilliant colours, and male fish develop a very noticeable nuchal hump that makes them very imposing fish. Despite their size, frontosa cichlids are quite gentle animals that do best kept in groups. They are predatory though, and will eat any fish small enough to swallow whole. Captive specimens eat all sorts of foods other than live fish though, including pellets. There are a few regional varieties available in the trade.
This is one of the ‘sardine cichlids’ that form schools in open water, feeding on plankton. They rarely swim anywhere but at the top of the tank, making them useful for adding movement and colour to a community tank without overcrowding the hiding spaces among the rocks. They also work as excellent dither fish, encouraging shy benthic cichlids to leave their burrows or caves and swim about in the open. They are basically hardy, but like other open water fish require lots of swimming space so are not suitable for small aquaria. Maximum size is about 12 cm, with males being more colourful than the females. There are numerous varieties in the lake, some of which are regularly traded.
One of the most widely traded of the ‘julies’, Julidochromis ornatus is a very pretty and basically easy to keep species, but like other members of its genus, it is rather secretive and rarely strays far from its cave. For this reason it is important to provide them with food at the lower level of the tank. Wild fish mostly scrape algae and small invertebrates from rocks. Maximum size is 10 cm, with no reliable differences between the sexes. They breed readily even in community tanks.
This cichlid is one of the most popular of all the Tanganyikans thanks to its basically tolerant personality and attractive colouration. Maximum size is about 10 cm, the female being a trifle smaller than the male. Matched pairs are very loyal to one another, and have proven to be excellent parents, to the degree than these cichlids routinely rear sizeable clutches of offspring even in community tanks. In aquaria at least, older juveniles will help their parents defend younger batches of fry. Easily satisfied in the aquarium, these cichlids eat most foods, though live or frozen crustaceans will help them develop their best colours.
Similar in size and shape to Neolamprologus brichardi, the ‘lemon cichlid’ Neolamprologus leleupi is one of the most dramatically coloured of the Tanganyikans. Depending on the variety, the basic colour is orange or yellow, with varying amounts of electric blue on the fins and fins. In terms of basic care they are similar to Neolamprologus brichardi but are a bit more aggressive and overtly territorial. Maximum size is 11 cm. In good condition, this is a superb cichlid that rivals any saltwater fish but aquarium fish often lack the bright colours of wild fish. A diet rich in carotene is important to prevent this, for which reason the aquarist should regularly provide these fish with plenty of live or frozen crustaceans as well as occasional mouthfuls of colour enhancing flake food.
Tropheus spp. are among the most aggressive Tanganyikans and are best considered fish for their own tank rather than the community. Another reason they should be kept alone is their diet. They are strict herbivores, and even small amounts of meaty food (such as flake or frozen bloodworm) causes them harm. The ideal diet for them is algae, either fresh or in the form of Spirulina flake, Sushi Nori, or similar. In terms of social behaviour, they should be kept as a colony of a dozen or more specimens. This will prevent bullying, but it does of course mean that these relatively large fish (around 14 cm) can only be kept in a big aquarium. Still, for all their problems these are beautiful fish, and there are lots of different varieties available. Tropheus duboisi is perhaps the mildest of all the Tropheus and has sometimes been kept in large Tanganyikan community aquaria, though this isn’t recommended.
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