A new species of Characidium is described from tributaries of the rio Paranã (Tocantins drainage), in Goiás State, central Brazil. Characidium stigmosum is diagnosed by the presence of dark marks along the sides of the body, which are associated with the vertical bars that occur in most species of Characidium. These marks are vertically oriented elliptical, except one or two anteriormost marks which may be roundish or horizontally elongate; there is usually one mark for each bar above abdominal area and two marks for each bar on posterior half of body; lower marks are slightly offset posteriorly. Characidium stigmosum shares apomorphic traits with the clade comprised of Characidium rachovii, Characidium occidentale, Characidium orientale, and Characidium vestigipinne.