Nannocharax dageti, new species, is described from southern tributaries of the Congo River basin in the Democratic Republic of the Congo and Zambia and the Kafue River basin of the Zambezi River catchment in Zambia. The new species is distinguished from its congeners by the pigmentation pattern consisting of vertically elongated, dark, rounded blotches overlapping a dark midlateral longitudinal stripe; the separation of the blotches in many cases from the dorsal saddles that extend to the middorsal line; the symmetrical coloration pattern on each caudal-fin lobe consisting of a dark spot on the base of each lobe and a series of dark spots forming a transverse narrow stripe across each lobe approximately one-third of the distance from the fin margin; a dorsal-fin origin situated anterior of the pelvic-fin origin; and the possession of 40 to 43 scales along the incompletely pored lateral-line series. Nannocharax dageti is apparently allopatric to other species of Nannocharax in southern tributaries of the Congo River.