The genusFarlowellahas been historically challenging, in part due to the difficulty in defining diagnostic characters which allow to clearly set apart and identify the species.Farlowella colombiensisRetzer & Page 1997 is one of such examples, whose diagnostic characters were based on caudal-fin colour pattern, body cover ventral pattern, and details of the head. We herein reassess the taxonomic status of this species against congeners of theF. acusspecies group (F. acus,F. martini,F. mitoupibo,F. venezuelensis, andF. vittata). We found no significant differences betweenF. colombiensisandF. acusin morphometric, meristic, and discrete characters, therefore renderingFarlowella colombiensisa junior synonym ofFarlowella acus. We provide remarks on different species of theF. acusgroup in Colombia, as well as description of sexual dimorphism in the genital papilla for the first time in the subfamily. We also provide a key to the species of theF. acusspecies group in Colombia.