Shell-dwellers: the shell-dwelling cichlids of Lake Tanganyika
By Daniela Rizzo
The cichlid family is much loved by hobbyists. Their diversity of shapes, sizes, colours along with their diverse habits and advanced parental care has ensured their enduring popularity. With a few exceptions they are easy to keep, and many species can be readily bred in home aquaria. Hundreds of species are available to hobbyists, and according to this author at least, there truly is a cichlid for everyone.
Cichlids come from many different habitats, from the shallow surge zone to open water and even at considerable depth in the larger lakes. In Lake Tanganyika there is a collection of cichlid species that live in empty snail shells know to hobbyists as the shell-dwellers or “shellies”. These are excellent choices for aquarists with small tanks, with some of them happily living and breeding in tanks as small as 40 litres (10 US gallons) in size.
Neolamprologus multifasciatus, one of the most popular shell-dwellers. © Bob Fenner
Given that these fish live inside snail shells, these fishes need to be small. Male Neolamprologus brevis for example reach lengths of just 4.5 cm (1.75 inches) while females are even smaller, around 3 cm (1.25 inches) long. These cichlids probably evolved from fish that lived in rocky cave, but pressure from competition and the many predators of Lake Tanganyika ensures that every possible niche is exploited, and these cichlids began to utilise the empty snail shells that litter the bottom of the lake.
Lake Tanganyika has very high levels of carbonate hardness, and the calcium in the water ensures that empty shells dissolve much more slowly than they do in most rivers and lakes. In some places there are piles of shells more than 3 metres (10 feet) deep. These shells provide a good way for small cichlids to find caves that they can use to protect themselves and their offspring.
Shell-dwellers are unusual in being highly sociable, and in the wild some species live in colonies, tolerating quite high densities within relatively small spaces. Together with their small size, this has quickly made them popular with aquarists looking to set up a small tank with lots of busy cichlids.
Maintaining shell-dwelling cichlids
A good size aquarium for shell-dwellers measures at least 40 litres (10 US gallons) in capacity, but a pair of the small, non-colonial species like Lamprologus brevis could be kept in as little as 25 litres (6 gallons). Shell-dwellers establish small territories around the empty shells, but their aggressiveness isn’t particularly high, and they will tolerate midwater tankmates well, provided those tankmates leave them alone.
Shell-dwellers are accomplished burrowers that love to dig around their shells, and will actually move their shells about until they are optimally positioned. Sometimes the shell will be almost completely buried, so use a fine burrower-friendly sand for the substrate, such as coral sand, that allows the cichlids to do this. The shell-dwellers will construct homes that allow them best access to the water current, since wild fish rely on water currents to bring them the tiny prey (zooplankton) upon which they feed.
Vallisneria plants do well in shell-dweller tanks, thriving in the necessary hard water. © Bob Fenner
The perfect aquarium settle for these fishes is one with a fine sand bottom, scattered with some stones and plenty of empty shells. But there should be plenty of empty space on the substrate as well. Not all shell-dwellers live exclusively in empty shells, and some species colonise the areas around stones, digging small burrows.
These fishes have well-defined preferences, and they’ll modify the aquarium decor as they see fit, and it’s good to allow them to do that. That will ensure peace and harmony in the aquarium, and almost certainly plenty of breeding. Shell-dwellers don’t damage plants, but they can dig them up, so if you want some greenery in your tank, put the plants away from the shells and stones. In my Tanganyikan community tank I have some Anubias and Cryptocoryne plants, and young Neolamprologus multifasciatus seem to enjoy exploring this area before they settle down into their own shells.
Water quality and chemistry
Like all Tanganyikan cichlids shell-dwellers need to maintained in aquaria with good filtration and regular water changes. In Lake Tanganyika the top 40 metres (131 feet) of water is very clear and rich in oxygen, and water quality is generally very high. Under aquarium conditions ammonia and nitrite levels need to be zero, and nitrate as low as possible, preferably below 20 mg/l.
The temperature varies from 23 to 27 degrees C (76 to 80 degrees F). The pH should be always higher than 7.5, ideally around 8.2, and the water must be hard or very hard, certainly not below 12 degrees GH.
Shell-dwellers live in shells, but what kind of shells? Where they can be found? In Lake Tanganyika they live in empty Neothauma spp. snails, but it isn’t necessary to use these. Helix pomatia shells packaged with canned escargot are available in delicatessen shops, and these are the perfect size and shape. Pomacea spp. apple and mystery snails also have shells that do the job if sufficiently large.
On the other hand, heavy saltwater snail shells, such as Turbo spp. shells, shouldn’t be used because the shell-dwellers will not be able to move them. Allow at least two shells per cichlid.
Apple snail shells make good homes for shell-dwellers like these Altolamprologus compressiceps Sumbu. © Neale Monks
Feeding shell-dwellers is simple. Wild fishes eat zooplankton and small invertebrates, although the bigger species like Lamprologus callipterus and Altolamprologus compressiceps “Sumbu” will also eat small fishes. In the aquarium they accept eagerly Cyclops, Mysis, Artemia, flake and pellets.
If they live in a community tank, be sure to pay attention that they eat enough food; they tend to stay near their shells, which may allow other inhabitants to take all the food before the shell-dwellers get a chance to eat. That said, I have an old female Neolamprologus multifasciatus who swims across an aquarium 300 cm long to feed, but she’s the exception to the rule.
The smallest shell-dwellers are also the best known species, Neolamprologus multifasciatus, Lamprologus ocellatus and Neolamprologus brevis. All three readily show their interesting behaviours in aquaria, making them popular all around the world. But there are several other species that traded as well.
Neolamprologus multifasciatus and Neolamprologus similis
Neolamprologus multifasciatus (commonly called “Multies”) and Neolamprologus similis are the two smallest cichlids in the world. They are colonial shell-dwellers; each individual has its own shell and territory, but they all live very close together, sometimes the shells forming piles! Neolamprologus similis is found living between rocks. The two species shouldn’t be kept together because they interbreed.
Neolamprologus multifasciatus is pinkish-brown with pale vertical stripes. Neolamprologus similis is very similar, but whereas the vertical stripes on Neolamprologus multifasciatus run from the gill cover to the base of the tail, on Neolamprologus similis the stripes run a bit further forward, with one stripe just behind the eye. Neolamprologus similis also tends to be a less widely sold.
Neolamprologus multifasciatus is a very popular and easily obtained shell-dweller. © Bob Fenner
In my community tank, Neolamprologus multifasciatus live in shells in the centre of territories, the males digging down to the glass bottom of the tank and forming barriers between their territories, a huge amount of work! Breeding occurs inside the female’s shell, the fry leave the shell when they’ve consumed the yolk, but they remain in their parents territory under their careful supervision.
Neolamprologus multifasciatus is fun to keep, and a fascinating fish for both single-species and community tanks. Some years ago I started with a pair in a 60-litre (15-gallon) aquarium. Before long they’d multiplied to such a degree that I needed to rehouse them in a bigger tank. I moved them into a Tanganyikan community measuring 300 by 80 by 70 cm (118 by 31 by 27 inches) where they live alongside Ophthalmotilapia ventralis “Sumbu”, Cyprichromis leptosoma “Utinta”, Neolamprologus cylindricus and others. The Neolamprologus multifasciatus have colonised a 50 by 50 cm (20 by 20 inches) area within which they’ve moved their shells. No other fish are allowed to remain in this zone, and all the other fish are chased away vehemently.
Lamprologus ocellatus is available in several varieties, though the most popular type is Lamprologus ocellatus “Gold”. This variety is bright yellow with a lavender sheen, and has a pugnacious attitude despite its small size.
Lamprologus ocellatus is another widely traded shell-dweller. © Neale Monks
Neolamprologus brevis is, as its name suggests, a very small cichlid. It is the only species in which males and females form stable, long-term pairs that share the same empty snail as hiding and brooding place. Neolamprologus brevis is another species that comes in a variety of patterns, including forms with vertical white lines on their bodies and others that are basically brown without stripes but with a prominent orange-yellow region between the gill covers and the anal fins. One variety may turn out to be a separate species; it is the smallest known cichlid in the world, and usually traded as Neolamprologus brevis “Minuta”.
Altolamprologus compressiceps “Sumbu”
Altolamprologus compressiceps “Sumbu” is a predator that lives in empty shell snails. Like other Altolamprologus spp., it is not very aggressive, but it does prey on smaller shell dwellers indeed it’s not recommended for community aquarium. Altolamprologus compressiceps “Sumbu” form pairs while breeding, but otherwise the two sexes live separately in their own shells.
Altolamprologus compressiceps Sumbu differs from other Altolamprologus compressiceps in its use of shells. © Neale Monks
Lamprologus callipterus is an interesting cichlid because only the females and immature males live in shells; sexually mature males are too big to enter the shells, being up to 12 centimetres (5 inches) long. Instead the sexually mature males swim about in large schools outside of breeding, becoming territorial when spawning. Males have a unique behavioural quirk: shell stealing! In fact a male will pick up a shell with its female and even her offspring from a previous liaison, and move them into his territory. The male will often eaten the fry that she already has, which gets the female into the right mood to spawn with him.
Neolamprologus leloupi is one of the species that only uses shells if caves aren't available. © Daniela Rizzo
Neolamprologus boulengeri, Neolamprologus hecqui and Neolamprologus meeli use empty shells as breeding sites, but only the females stay inside and tend the eggs, the males instead patrolling the territory and chasing away potential threats.
Neolamprologus leloupi and Neolamprologus caudopunctatus don’t live in shells, and will only spawn inside empty snail shells if there aren’t any suitable caves or crevices. My Neolamprologus leloupi pair would consistently breed in small caves even though there were lots of suitably-sized shells available.
All the shell-dwellers have interesting behaviour, and it’s a pity that they are often relegated in small tanks. They can cohabit with larger cichlids, if peaceful, and will brighten up community tanks significantly.
Take care when combining shell-dwellers with larger tankmates such as Neolamprologus brichardi. © Bob Fenner
In a large aquarium it’s possible to keep two species of shell dwellers together the providing shells are in at least two different areas of the tank, so that each species can create its own colony. I have also kept a true shell-dweller, Neolamprologus multifasciatus, alongside an opportunistic one, Neolamprologus leloupi without problems. These nice, little fishes are certainly worth enjoying!
Enjoying Cichlids, Kjell Fohrman, Mary Bailey and Ad Konings; Cichlid Press 2002
Tanganyika Cichlids in their Natural Habitat, Ad Konings; Hollywood Import & Export Inc. 1998