Aquarist Atlas
↑ Collection form of Petrochromis polyodon

Petrochromis polyodon "Mtoto"Tanganyika grinder

Petrochromis polyodon (Cape Chaitika, Cape Kachese, Cape Nangu, Chituta Bay, Kalala Island, Kalambwe, Kambwimba, Kantalamba, Katete, Kombe, Moba, Mtoto, Nausingili Island, Ndole Bay, Samazi, Tembwe Deux, Zambia, Zongwe)

Mtoto — m-TOH-toh (approx.)

The fish

How this cichlid is built, and everything about how it lives, eats and breeds, is shared with the species — this page doesn't repeat it.

Read the full Petrochromis polyodon account →

Specific to Mtoto

  • Collection locality & coordinates
  • Local coloration — best judged from the living-fish photo
  • Kept as a single-provenance line, never crossed with other collection points

Care facts below are the species' — shared with Petrochromis polyodon.

IUCNENDANGERED · 2025
CARESNOT LISTED
Genus type speciesPetrochromis polyodonBoulenger 1898 · this species
Scientific size8.5 in21 cm total length
Temperature73–79 °F23–26 °C
pH7.2–8.5alkaline
Habitat waterhard · 600–690 µS/cmLake Tanganyika
Depth0–23 ft0–7 m
DietHerbivore; scrapes epilithic algae (aufwuchs — diatoms, unicellular algae, fine organic film) from rock surfaces using dense comb-like tricuspid teeth
Breedingmaternal mouthbrooderFemales 12.6–14.1 cm SL brood eggs from cleavage stage to free-swimming larvae ~2.83 cm
Sexual dimorphismYesMales generally larger; dominant territorial males develop stronger coloration including blue iridescence on head and unpaired fins; females and subordinate fish remain plainer
PhotographsSee photosGoogle Images →

The Mtoto population

Petrochromis polyodon "Mtoto" is the Mtoto population of Petrochromis polyodon, a geographic colour form from the Democratic Republic of the Congo coast of Lake Tanganyika in the north-central part of the lake. It is the same species as Petrochromis polyodon, distinguished by its collection locality and local coloration; aquarists keep and breed it as a discrete, provenance-labelled line.

Colour reference: living Mtoto fish at tanganyika.si →

About the species

Petrochromis polyodon is the type species of Petrochromis, a genus of rock-grazing cichlids found nowhere on Earth but Lake Tanganyika, and it earns its keep by scraping a living off stone. A mouthful of dozens of fine, comb-like teeth lets it brush diatoms and algal filaments from the rock face the way a wire brush works a grill, and on the lake's sunlit reefs it is one of the most committed and aggressive grazers of them all. Reaching about 8 inches (8.5 in), it holds a feeding territory it will defend against almost anything, packs the same intensity into a tank, and is, as of a 2025 reassessment, now formally listed as Endangered — a status that says as much about its shallow, sediment-prone home as about the fish itself.

Full Petrochromis polyodon account →

Sources

  1. tanganyika.si — Petrochromis polyodon "Mtoto"
  2. Eschmeyer's Catalog of Fishes — Petrochromis polyodon Boulenger, 1898
  3. FishBase — Petrochromis polyodon (Boulenger, 1898)
  4. FishBase — Food and Feeding Habits Summary, Petrochromis polyodon
  5. GBIF — Petrochromis polyodon (Boulenger, 1898)
  6. Boulenger (1898), Proc. Zool. Soc. London — Report on the fishes recently obtained by Mr. J. E. S. Moore in Lake Tanganyika (original description; via CRC reference archive)
  7. IUCN Red List — Petrochromis polyodon "Mtoto"
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