Nematocharax is a genus of freshwater fish in the family Characidae. It contains the single species Nematocharax venustus, which is endemic to Brazil, where it is found in the Jequitinhonha River basin. The males of this species can reach a length of 5.1cm (02inches) SL while the females only grow to 3.5cm (01.4inches) SL.[1]