Author: (Spix & Agassiz, 1829)
Remark: Redescribed in Ferraris & Vari (1999).
Comments: Inhabits lower courses of the larger rivers.  Free swimming species found near the surface.  Nocturnal, plus active during dusk and dawn.  Feeds on smaller fish.  The male is recognizable by his thick, ossified maxillary barbels and by the first few rays of the anal fin which are fused, supporting the urogenyla tube that runs along the anterior border to the tip of the rays (Ref. 6868).  This fish comprises the majority of the catches in the fish nets and is especially captured during the rainy season which is its reproductive period.  Occurs less frequently in flood zones, prefers eroded zones where it appears in large numbers (Ref. 27188).