Lake Tanganyika, with its more than 300 indigenous cichlid species, is going to be the focus of this column for the next few months with the setting up of a multi-cichlid community aquarium.
Lake Tanganyika is a Great Rift Valley lake in East Africa that is 420 miles long but just 40 miles across at its widest points. But it can get as deep as 4,700 feet in places, although no fish live at this depth since the water here is relatively unoxygenated. Around the lake’s coastline the water is shallower, which is where we are going to focus our search for suitable cichlid fish. This vast body of water has a range of entirely different habitats that has resulted in the evolution of the cichlids to give rise to new species to exploit each habitat. One of the habitats in Lake Tanganyika is the sandy bottom habitat that ranges from the rocky coastline to further afield. Some areas of the sand floor are littered by empty Neothauma sp. snail shells, which naturally some small cichlids species have adapted to exploit by utilizing the shells as homes. One such cichlid is Neolamprologus brevis.
Neolamprologus brevis (Boulenger, 1899) has a fairly wide distribution around Lake Tanganyika, although the standard N. brevis variety, with a brown base color and nine tan vertical stripes, are imported from Kigoma, Tanzania. The sunspot N. brevis variety, with a gold spot behind each of the pectoral fins and a brownish mauve body, is from Ikola, which is further south on Lake Tanganyika. The zebra N. brevis variety is reputed to be especially colorful with more defined vertical stripes in both male and female fish. In all varieties, the body color and barring does extend into the caudal fin as well as the dorsal and anal fins, both of which are long-based and all of which make for some rather handsome cichlid fish. Neolamprologus brevis are true dwarf cichlids since the males only grow to a little more than 2 inches, while the females usually remain smaller at less than 1½ inches.
Neolamprologus brevis are found within snail shells on sandy bottoms at depths from 15 to 150 feet. Here a male and female may share the same shell if necessary, depending on the number-of-shells-to-fish ratio in the locality. Using their mouths as shovels, N. brevis like to excavate the sand from around their shell, causing it to sink into the sand. The shells are also physically tugged into place so that the opening is pointing in the correct direction.
In the wild, N. brevis stay in close proximity to their shell so that they can make a quick dive into it if danger approaches. These cichlids don’t have to travel to feed, as the zooplankton they eat is constantly being carried on the water current that passes by their shell homes. All they do is hover in the water current above their shell to catch food.
With the intention of setting up a Tanganyikan biotope aquarium to house four or five different species of small- to medium-sized cichlids, a reasonably sized aquarium is called for. All the other species are going to be bigger than the N. brevis cichlid fish. While N. brevis are tied to a shell or two and have a small territory, the other cichlids to be added later have different territorial requirements.
The smallest suitable aquarium size for this mixed Tanganyikan cichlid society is 48 by 24 by 24 inches and 120 gallons. Or, at this stage, aquarists could decide on a single-species aquarium that is just 24 by 12 by 12 inches and 15 gallons, which would be suitable for two pairs of N. brevis to enliven the aquarium with their interactions.
Working with the larger tank first, the intention is to build it up with essential décor to provide for specific needs of individual cichlid species just prior to the time that they are to be added to the system.
All that a pair of N. brevis need is two or three Neothauma-sized shells placed directly on top of a 2- to 3-inch-deep bed of mixed smooth-grain sand and coral sand. The coral sand helps maintain the alkalinity and hardness of the water. This does leave a bare-looking tank for the first month, but soon there will be more additions to the tank as the community is slowly built up.
The smaller tank only needs the substrate of smooth-grain sand and coral sand to be 1 inch or so deep. Two groups of three or four Neothauma or other similar-sized empty shells are placed at each end of the aquarium to offer prospective homes to the two pairs of cichlid fish. The back of the aquarium can be decorated any which way with some rock.
Lake Tanganyika has a high mineral content, making the water alkaline and hard (pH of 7.5 to 8.5; dGH of 12 to 18). It is vital that the water in these aquariums reflects the natural habitat, because in soft water these cichlid fish will probably be subjected to lingering deaths. Water temperature in this large lake is fairly stable at around 75 degrees Fahrenheit, which is what one should aim for in this setup. The larger aquarium will benefit from an external canister filter that also provides a good current of water in the aquarium.
With the smaller cichlid aquarium, a filtration unit located inside the aquarium that also provides a current should be adequate for this low-stocked aquarium. Regular partial water changes of 10 percent are necessary to maintain the aquarium water in top condition.
Selecting male and female N. brevis from subadult fish is easy, as the male is much larger than the female comparatively. At the fish store, if the N. brevis tank has shells, the cichlids quickly disappear into them at the sight of an approaching net. Catching the cichlid then involves just picking up the shell with fish inside and placing it in a bag of water. As a result, one might end up having the shell thrown in as a bonus.
The N. brevis should be offered a mixed diet that could include some flake food and tiny pellets fed in small amounts two or three times a day. They are not fussy eaters and so readily accept these fish foods. They should also be offered some live or frozen brine shrimp at least once a week. Care should be taken not to overfeed them or, even worse, to allow food to lie uneaten in the aquarium, as it quickly rots and spoils the water.
A healthy adult pair of N. brevis that are fed a good diet will spawn, provided they have a suitably sized shell to call home. Once the female has filled up with eggs, following some prespawning behavior, the female lays its eggs within the shell. The male may fertilize the eggs by entering the shell or from the shell entrance if it is too big to enter. The female does all the egg care, while the male keeps intruders away from the shell. The eggs take some 48 hours to hatch, but it might well be another seven days before the fry make their first appearance near the entrance of the shell. At this time they will be able to take crushed flake, newly hatched brine shrimp and microworms, which should all be offered in moderation. The slow-growing fry will stand a chance of surviving if several smaller shells are available for them to take refuge in.
Although Lake Tanganyika does contain many large cichlid fish, dwarf N. brevis are beautiful little fish that are easy to keep and maintain in a small tank or as part of a Tanganyikan cichlid community. A pair of these little cichlids that live in a shell are interesting and entertaining to watch as they go about their daily lives, guarding their home from intruders and raising their brood. Next Page>>