Tropheus duboisi Marlier, 1959Curator: Patrick Tawil. Last updated on 28-May-2010.
Original description as Tropheus duboisi:
Taxonomic history:
Groupings:
Etymology: The species is dedicated to J. Dubois, collaborator of G. Marlier. Diagnosis: Tropheus duboisi differs from all others Tropheus by its narrower, rounded, sub-terminal mouth (vs. squarish, down-turned and broad). Differs also by its color patterns: blue head and black body in adults, with a more or less broad white to yellowish band on the chest, and black with rows of white dots in juveniles. 5 spines in anal fin. Size: Up to 14 cm total length in imports, sometimes more than 15 in aquarium. Females usually slightly smaller than males. Type locality: Memba, Lake Tanganyika, Congo. Distribution: A comparatively low number of populations is known. The only congolese population comes from the type locality (Bemba). On the eastern coast, the species is found, from north to south, at Nyanza-Lac, Kigoma, Halembe and Karilani. The so-called "Maswa" duboisi, which shows the broadest and most yellowish band, comes from Halembe and surrounding areas. Inhabited countries: Burundi, Congo, Democratic Republic, Tanzania (native). Habitat: Inhabits rocky shores, where it is usually pushed down by its more evolved congeners of moorii type to deeper layers (up to 30 m, usually more abundant between 6-10 m) and less favorable sediment-rich areas. Habitats: Halembe (Tanzania), Karilani Island (Tanzania), Kigoma (Tanzania, native), Maswa (Tanzania). Feeding: Feeds from the rock algal bio-cover (aufwuchs) which is teared in a less efficient fashion than other Tropheus, since the mouth is narrower and less down-turned, thus increasing the angle between the body and the substrate. Breeding: As other members of the genus, Tropheus duboisi is a maternal mouth-brooder which produces a rather low egg number (usually from 6-20). In compensation, the pear-shaped eggs are among the largest in the family (7 mm in the longest diameter), giving birth to rather large and well developed young. The incubation period is basically of 3 weeks, but often continues during several more weeks (up to 10), during which the young are released from time to time by the mother in sheltered areas of may feed inside their mother's mouth. The male does not take any part in the parental care and usually chases the female immediately after the spawn, but in aquarium, may tolerate her in the immediate surrounding of his territory. Aquaristics: Despite its marked morphological differences and lower population density in natural habitat, Tropheus duboisi does not differ markedly from its congeners in aquarium. The widespread supposition that Tropheus moorii types are gregarious species while Tropheus duboisi is mainly solitary is unfounded, since the lower population density of Tropheus duboisi is mainly related to is lower ecological success. In aquarium, males of all Tropheus species tend to defend their own territory, while linear hierarchies are found only in case of overcrowded small tanks. In order to observe their natural behavior in aquarium, Tropheus must be kept in small groups of several males and females in large tank (at least 500 l, preferably 1000 l or more) together with other tropheines such as Petrochromis or Simochromis. In smaller tanks, their murdering tendencies usually lead to the eradication of all subordinate males and females, unless the tank is markedly overcrowded. In some cases, when the sexes fit well together, they may be kept as a single pair, a situation which may last several months or years, until the male may finally kill his mate by frustration. Conservation: Tropheus duboisi is evaluated by the International Union for the Conservation of Nature in the IUCN Red List of Threatened Species as (VU) Vulnerable (2006). This restricted range species is rather sensitive to over exploitation for the aquarium trade; the "Maswa" form is reputedly over fished, and is less often available in the imports. Comments: Considering its narrow sub-terminal mouth, less specialized than in Tropheus moorii types, Tropheus duboisi is probably the most primitive species in the genus, and may even deserve a genus or, preferably, a subgenus of its own. Despite some resemblance in coloration with Tropheus sp. 'black' (black pattern with a broad band on the body), Tropheus duboisi shows a peculiar juvenile color pattern (black with white dots). This color pattern is definitively lost with sexual maturity, while other members of the genus are still able to show it in sub-dominate individuals (especially females), except again for Tropheus sp. "black" (including the Ikola form). Petrochromis trewavasae also shows a juvenile pattern with rows of white dots, but it is not permanently lost in adulthood. Other pictures (15):
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