Micralestes acutidens (Peters, 1852)
Sharptooth tetra
Micralestes acutidens
photo by Gratwicke, B.

Family:  Alestidae (African tetras)
Max. size:  9 cm SL (male/unsexed); max.weight: 2.0 g; max. reported age: 3 years
Environment:  pelagic; freshwater; pH range: 6.19999980926514 - 8; dH range: 25, potamodromous
Distribution:  Africa: Congo, Okavango, Zambezi (Ref. 7248, 120641), Kunene and east coast rivers south to the Pongolo (Ref. 7248), Cross and Sanaga Rivers (Ref. 80290) and Tanzania (Ref. 4967). Nilo-Sudan and West-African reports of M. acutidens (e.g. Ref. 367, 51193) are misidentifications of M. elongatus (see DVD version of Ref. 81279; see also Ref. 2880).
Diagnosis:  Dorsal spines (total): 0-0; Dorsal soft rays (total): 10-11; Anal spines: 0-0; Anal soft rays: 17-20. Diagnosis: inner dentary teeth multicuspid; 14-17 anal fin branched rays; dorsal fin apical tip black; scales of flank without melanophores concentrated along basal margin, pigment diffuse or absent (Ref. 80290). Description: body moderately slender; body depth 30-33% and head length 24-29% of SL (Ref. 80290). Body height 3-3.5x and head length 3.6-4.2x in SL (Ref. 42032). Mouth terminal, upper lip prominent, depth of lower jaw about 1.5 that of upper jaw (Ref. 80290). Lower jaw projects (Ref. 4967). Premaxilla with 3 teeth in outer row each bearing 7-12 cusps; dentary with 4 teeth in outer row each bearing 9-12 cusps, median cusp prominent, a multicuspidate tooth at symphysis posterior to outer row dentary teeth; lateral line complete, 26-29 tubes, ultimate canal-bearing scale terminal; anal fin with 3 unbranched and 14-17 branched rays (Ref. 80290). Coloration: black lateral band from posterior opercular margin to caudal fin base (Ref. 42032, 80290), underlain by broad band of silver pigment in life (Ref. 80290). Band width and pigmentation density increase caudad and greatest at vertical through anal fin origin; dorsal fin with dark mark at apical tip involving frist 3-4 branched rays; adipose fin without pigment; caudal fin lobes often brilliant red in life (Ref. 80290). Fins greyish (Ref. 42032).
Biology:  Shoals in clear, flowing or standing, open water; appears to co-exist with the tigerfish Hydrocynus forskalii in open water although it is heavily preyed upon by that predator, particularly those shoals of tigerfish ranging up to 45 cm in length (Ref. 13337). Omnivorous, often feeding from surface waters on winged insects; also takes insect larvae, crustaceans and eggs and fry of other fish (Ref. 13337). Matures after a year; partial spawner of moderate fecundity, with usually fewer than 700 eggs per female; shoals migrate upstream after first summer rains; breeds throughout the summer months; used as forage fish and as bait for tigerfish and pike (Ref. 7248).
IUCN Red List Status: Least Concern (LC); Date assessed: 30 April 2018 Ref. (130435)
Threat to humans:  harmless


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