This large genus of characins includes over 100 species. The systematics of Hyphessobrycon is still largely unresolved. Six groups within this genus have been recognized based on color patterns alone. With no phylogenetic analysis of this genus, species are placed into this genus as anatomically defined by Carl H. Eigenmann in 1917. By this definition, Hyphessobrycon is identified by the presence of an adipose fin, incomplete lateral line, two tooth series in the premaxilla, with the teeth of the external series continuous in a single series, teeth not strictly conical, preventral scales arranged in more than one row, and lack of scales in the caudal fin. The characteristic of extension of scales onto the caudal fin that differentiates.