Dorsal spines (total): 11 - 13. Body slender and subcylindrical, compressed posteriorly. Mouth large, slightly oblique, contained in underside of head. Teeth minute, in narrow bands on both jaws. Barbel slender, usually about as long as 2/3 diameter of orbit. Scales large, thin, and cycloid. Luminous organ elongated and with 2 external lenses. Black streak present along anterolateral margin of snout, along upper margin of orbit, along inner margin of each lip, and along both sides of mandibular sensory canal. Ventral striae, consisting of alternate lines of black and silver, well developed on isthmus and on ventral regions. Luminous organ, except for lenses, jet black.