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Lake Tanganyika cichlids — species, locations & maps

Lake Tanganyika cichlids — species, locations & maps
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Petrochromis famula 'Kalambo Lodge'.jpg Petrochromis fasciolatus 'Kalambo Lodge'.jpg Petrochromis horii 'Kalambo Lodge'.jpg Shuja horei 'Kalambo Lodge'.jpg Simochromis diagramma 'Kalambo Lodge'.jpg
Previous pageNext pagePetrochromis horii 'Kalambo Lodge'
Tribe / Genus: Tropheini / Petrochromis
Type locality: Kasenga, Zambia.
Biotope: Occupies rocky habitats and likely also intermediate sand–rock environments, restricted to greater depths. Territorial males are found deeper than 20 m, where territories are only weakly defended, while females occur at somewhat shallower depths of about 10–15 m and do not hold territories.
Geographic distribution: Occurs in the southernmost part of Lake Tanganyika, confirmed at Kasenga in Zambia, and is likely distributed further both eastwards and westwards along the southern basin of the lake.
Typical adult size: Little is known about adult size. In the type series, the largest specimen was a female measuring about 14 cm. Males are assumed to be significantly larger than females, as in other members of the species group, but confirmed observations of fully adult males are lacking.
Sexual dimorphism: Poorly documented. Available material suggests females are smaller, while males are presumed to be larger, although this has not yet been directly observed.
Recommended aquarium size: An aquarium of at least 500 L is recommended.
Aquarium setup: Provide extensive rockwork arranged into separate rock piles to create loosely defined territories, while maintaining ample open swimming space between structures. A sandy substrate is recommended.
Strong filtration is essential due to the large amount of food consumed and the resulting waste production.
Diet: Herbivorous grazer. In nature it feeds mainly on algae scraped from rocks. In aquaria, it should be offered a diet rich in vegetable matter, particularly spirulina-based flakes or pellets.
Breeding: Maternal mouthbrooder.
The male attracts the female to his territory, where spawning occurs. Eggs are collected into the female’s mouth, and fertilization takes place inside the mouth during interaction with the male’s egg spots.
Broods are relatively small, usually around 15 eggs in nature and often around 30 in aquaria. After roughly 30 days the female releases well-developed fry and continues feeding during the brooding period.
Aggression: Generally aggressive toward conspecifics, though members of the Petrochromis horii species group are notably less aggressive than shallow-water Petrochromis. This reduced aggression is likely related to their deep-water habitat. Toward other species, aggression is limited, although males may weakly defend territories.
Special notes: Petrochromis horii belongs to the so-called Petrochromis horii species group, referred to by Ad Konings as “Petrochromis of the deep”. According to African Diving Ltd, this group comprises four distinct species. Because these Petrochromis inhabit depths greater than 20 m (with territorial males occurring even deeper), all members of the group remain poorly studied.
Members of the P. horii species group are distributed throughout the southern part of Lake Tanganyika, occurring along the central Tanzanian coast in Mahale National Park, continuing along the entire southern Tanzanian shoreline, through Zambia, and further along the southern Congolese coast as far as Cape Tembwe (according to African Diving Ltd). Exact distribution boundaries between the individual species of the group are largely unresolved due to their deep-water habitat and the resulting lack of comprehensive observations.
The group currently includes the following forms:
  • Petrochromis horii – the only formally described species of the group, yet arguably the least known. Apart from photographs by Adrian Indermaur from Kapwensolo and Kalambo Lodge, very few images exist beyond those used for the original description. The species was described from specimens collected at Kasenga, Zambia, where the largest individual was a female measuring about 14 cm. Takahashi & Koblmüller (2014) therefore suggested the possibility of females being larger than males, a hypothesis P. Tawil considers highly unlikely, maintaining that males are probably substantially larger, although this remains undocumented. Apart from the mentioned Zambian localities in the extreme south-eastern part of the lake, no confirmed records from other areas exist.
  • Petrochromis sp. ‘gold’ – included within P. horii by Ad Konings in Tanganyika Cichlids in their Natural Habitat (4th edition), although he notes that further research may show it to represent a distinct species. According to Konings (2019), it occurs from Katete in Zambia to Mtoto in the Democratic Republic of the Congo, while African Diving Ltd report its presence as far as Cape Tembwe. The name refers to the bright yellow coloration seen in subadult individuals; adult males are instead grey with vertical barring.
  • Petrochromis sp. ‘red’ – found in the area between Lyamembe and the Lubulungu River. With the exception of Lyamembe, which lies just outside Mahale National Park at the southern edge of the range, the entire distribution is located within Mahale NP. In the aquarium hobby, this species is often incorrectly referred to as Petrochromis sp. 'Red’ Bulu Point', although it does not occur at Bulu Point. The use of this locality name is likely related to fishing restrictions within Mahale Mountains NP, with Bulu Point being just north of the protected area. The species is also sometimes mislabeled as originating from Sibwesa, but no suitable habitat exists there and the species does not occur at that location.
  • Petrochromis sp. ‘red mpimbwe’ – the name used by African Diving Ltd; referred to by Ad Konings as P. sp. ‘kipili brown’, and by P. Tawil simply as P. sp. ‘brown’, all three names referring to the same form. This taxon is reported from Cape Mpimbwe southwards to Kambwimba, slightly north of the Kalambo River. Specimens from the Kambwimba and Kasanga areas are commonly known in the aquarium hobby as “Petrochromis Flametail”. African Diving Ltd and Ad Konings consider “Flametail” conspecific with P. sp. ‘red mpimbwe’ (= P. sp. ‘kipili brown’), whereas P. Tawil suggests Flametail may be closer to P. horii. This discussion is detailed by P. Tawil in “The deep-water Petrochromis” (Tanganyika Magazyn, issue 20).
All four members of this group share a deep-water lifestyle and one particularly rare trait among Tropheini: the absence of false egg spots on the anal fin.

Photo: © Adrian Indermaur
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