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Lake Tanganyika cichlids — species, locations & maps

Lake Tanganyika cichlids — species, locations & maps
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Ophthalmotilapia nasuta 'Milima Island'.jpg Paracyprichromis brieni 'Milima Island'.jpg Petrochromis orthognathus 'Milima Island'.jpg Tanganicodus sp. 'kavalla' Milima Island.jpg Telmatochromis sp. 'vittatus elongate' Milima Island.jpg
Previous pageNext pagePetrochromis orthognathus 'Milima Island'<br><font color=gray>Interochromis orthognathus 'Milima Island'</font>
Tribe / Genus: Tropheini / Petrochromis
Type locality: Lake Tanganyika.
Biotope: Rocky substrates in shallow littoral zones, typically between 0.5 and 5 m depth. Inhabits hard, algae-covered rocks within the photic zone of the lake.
Geographic distribution: Restricted to the northern two thirds of Lake Tanganyika. In the Democratic Republic of the Congo it occurs from Tembwe (Deux) to Uvira. Along the eastern shore it is found throughout Burundi and southwards in Tanzania at least to Pasagulu Point, and probably as far as Miyako. South of the Lubulungu River, between Luagala Point and Cape Mpimbwe, it is replaced by the similar species Petrochromis sp. ‘orthognathus ikola’.
Typical adult size: Reaches a maximum total length of about 16.5 cm.
Sexual dimorphism: Males grow larger than females and typically show more elongated dorsal and anal fin extensions. Males may display brighter coloration, especially during breeding periods.
Recommended aquarium size: May be kept in aquaria from about 600 L upward, provided space, structure and filtration are adequate. Larger aquaria are advantageous for long-term maintenance.
Aquarium setup: A rocky aquarium replicating shallow Tanganyika shores, with extensive rock piles forming caves, grazing surfaces and loosely defined territories, combined with a sandy substrate.
Strong filtration, good water movement and high oxygenation are required. Water should be hard and alkaline (around pH 8.2) with stable temperatures between 23–26 °C. Bright lighting is beneficial to promote algal growth on rocks.
Diet: Strictly herbivorous grazer feeding primarily on aufwuchs, including algae, diatoms and associated biofilm scraped from rocks. In aquaria, it requires a vegetable-based diet such as spirulina-rich flakes or pellets and blanched greens; high-protein foods should be avoided.
Breeding: Maternal mouthbrooder. Spawning takes place on the substrate within the male’s territory, after which the female immediately collects the eggs into her mouth. The female incubates eggs and larvae for approximately 4–5 weeks before releasing free-swimming fry.
Aggression: Highly territorial and aggressive, especially among males. Dominant males vigorously defend large territories against conspecifics, forming strong dominance hierarchies. Aggression is intense and can result in serious injury or death in confined conditions.
Special notes: The species name orthognathus refers to its straight, equal jaws, a distinctive feature within the genus. The orthognathous mouth, together with densely packed tricuspid teeth, is adapted for efficient scraping of algal biofilm from rocky surfaces.
Petrochromis orthognathus is a diurnal, benthopelagic herbivore that typically occurs solitary or in loose aggregations over rocks. It plays an important ecological role as a primary consumer, contributing to the regulation of algal growth in the littoral zone of Lake Tanganyika.

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Photo: © Ad Konings
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Lake Tanganyika cichlids — species, locations & maps.
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