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Common names:
Sadler's robber
Local: Nsoga

Taxonomic tree
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii (ray-finned fish)
Order: Characiformes (Characins)
Family: Alestidae (African tetras)
Genus: Brycinus
Species: Brycinus sadleri (Boulenger, 1906)
Number of Occurrancies: 445

Etymology (based on Scharpf & Lazara, 2019)

  • Brycinus: –inus, an adjectival suffix, Brycon-like (general term for characiform fishes), derived from bryco, to bite, gnash teeth or eat greedily, originally an allusion to fully toothed maxillae.

  • sadleri:  in honor of Lieut.-Col. James Hayes Sadler (1827-1910), Commissioner of the Uganda Protectorate when type was collected.

Synonyms: click here to view synonyms

Type locality: Lake Victoria, Entebbe, Uganda. Lectotype at British Museum of Natural History (BMNH)

Distinguishing characters for the genus

  • Short snout

  • Small and non-protractile mouth; teeth firmly fixed, those of the outer series stout and not compressed basally

  • Two series of functional multi-cuspidate teeth in the upper jaw, the outer series usually tri-cuspid and less massive than the stout, many cusped teeth in the inner series 

Distinguishing characters for the species

  • Intensely silver lateral streak runs from behind the operculum to the caudal peduncle, where it merges with an irregular black blotch which extends into the caudal fin base (Diagnostic)

  • After death the longtidunal band darkens, and is turns black in preserved specimens (diagnostics)

  • Smaller lateral line scales 31-34, 6.5-7, usualy 7, scales between the lateral lines and the origin of the dorsal fin (Diagnostic)

  • Anal fin with 20-21 rays, the first three unbranched (Diagnostic)

  • Depth of the body contained up to 3-4 times in standard length, and length of the head 3.5 (in young) to 4 times

  • Head 1.75 to twice as long as broad; fronto-parietal fontanelle absent

  • Snout rounded, equal or slightly longer than the eye, whose diameter is contained 2.5 (in young) to 4 times (in adults) in the head length

  • Adipose lids are barely visible

  • Maxilla not reaching the anterior orbital margin

  • 8 teeth in each of the upper jaw series, 8 and 2 in the outer and inner lower jaw series

  • Gill rakers moderately long, 16-18 on the lower limb of the first gill arch

  • Dorsal fin with 10 rays, the first two unbranched; its origin above the pelvic fin insertion

  • Colour is Silver, bluish-black dorsally. All fins grey. 

Taxonomic remarks: The species is commonly reported in old literature as Alestes sadleri, which is currently a senior synonym (Froese and Pauly, 2019). In general appearence, B. sadleri closely resembles Brycinus nurse and Brycinus jacksonii. It differs from these two species principally in having more anal fin rays (20-21) compared to 18 or 19 in B. jacksonii and and 11-14 in B. nurse, and smaller scales (31-34) in lateral line series  compared to 25-29 in B. jacksonii and 30 in B. nurse.

Distribution in Uganda: Lake Victoria (and some affluent rivers and streams), Lake Nabugabo, Lake Kyoga, Victoria Nile and Aswa

Occurence: Native

Habitat: Pelagic, common in shallow waters amongst marginal vegetation forming shoals.

Feeding: Insectivorous, chiefly chironomid pupae.   

Biology: Adult sizes are smaller compared to other Robbers, and may not exceed 15 cm long. No specific information on breeding, but apparently run up the rivers and streams during rainy seasons to spawn.

Economic importance/End use: The species is not common in catches because of their small size

IUCN conservation status: click here to view IUCN status

Threats: Predation by Nile perch

Main references

  • Greenwood PH. 1966. The fishes of Uganda. The Uganda Society, Kampala. 131 pages.

  • Sharpf C, Lazara J.K. 2019. Fish Name Etymology Database v17.

  • Froese, R. and D. Pauly. Editors. 2019. FishBase. World Wide Web electronic publication.,  version (12/2019).

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Natugonza, V. & Musinguzi, L. (editors) 2021. Freshwater Biodiversity Portal for Uganda., version (01/2021).


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