Nannopetersius ansorgii (Boulenger, 1910)

Family:  Alestidae (African tetras)
Max. size:  7 cm SL (male/unsexed)
Environment:  pelagic; freshwater; pH range: 6.5; dH range: 12,
Distribution:  Africa: Benito (Mbini), Chiloango, Kouilou, Loeme and OgoouĂ© rivers of Gabon and Equatorial Guinea (Ref. 80290) and the Bengo and Congo River basins of Angola and Democratic Republic of the Congo (Ref. 80290).
Diagnosis:  Anal spines: 0-0; Anal soft rays: 21-25. Diagnosis: 14-17 gill rakers on lower limb of first arch; flanks with lateral pigment band, more or less restricted to posterior third of trunk and caudal fin base, extending onto median caudal fin rays; dorsal and ventral caudal fin lobes not pigmented (Ref. 80290). Description: body relatively robust, body depth 35-40% of SL and head length 25-28% of SL; mouth terminal to slightly superior, lower jaw prominent, its depth about 1.5x that of upper jaw; premaxilla with 2 teeth in outer row each bearing 3-5 cusps, 4 teeth in inner row each bearing 5-7 cusps; dentary with 4 teeth in outer row each bearing 5-7 cusps, a monocuspid inner dentary tooth present posterior to outer row teeth; lateral line canal complete, 32-35 tubes, ultimate canal-bearing scale contacting caudal fin rays by 1-2 non-canal-bearing scales; anal fin with 3 unbranched and 19-22 branched rays (Ref. 80290). Coloration: flanks silvery, with dark lateral pigment band more or less restricted to posterior third of trunk and caudal fin base, extending onto median caudal fin rays; band especially prominent at caudal fin base and on medial fin rays, yielding a strong diamond-shaped mark; dark humeral spot present; opercle with dark diffuse pigment; fins generally yellowish to dusky, margins trimmed in dark pigment (Ref. 80290).
Biology: 
IUCN Red List Status: Least Concern (LC); Date assessed: 01 May 2009 Ref. (130435)
Threat to humans:  harmless


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