Roeboides prognathus (Boulenger, 1895)
photo by Sazima, I.

Family:  Characidae (Characins; tetras), subfamily: Characinae
Max. size:  18.5 cm SL (male/unsexed); max.weight: 76.0 g
Environment:  benthopelagic; freshwater
Distribution:  South America: Paraguay, middle and lower ParanĂ¡, and Uruguay River basins.
Diagnosis:   
Biology:  Inhabits inlets and backwater of rivers and slow-flowing streams. Forages mostly at twilight, stalking larger fishes to feed on their scales. Approaches its prey stealthily and usually aims at prey's flank. Its translucent body likely favor this stealthy approach. Strikes at prey mostly with its mouth closed, dislodging the scales with its stout, external and forward directed foremost premaxillary and dentary teeth. These teeth are often worn and sometimes missing, the differential teeth wear indicating right or left-handedness of a given individual (Ref. 28733). The jarring strike dislodges a few scales which are swallowed immediately if taken in the mouth, or are picked up as they sink. Besides scales, it feeds on aquatic insects. Juveniles up to 3 cm still do not bear the stout external teeth, hence feed mostly on insects and tiny crustaceans (e.g. ostracods) (Ref. 40383).
IUCN Red List Status: Not Evaluated (N.E.) Ref. (130435)
Threat to humans:  harmless
Country info:   
 


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