Gogo atratus is a new species of anchariid catfish described from the Mananara du Nord River drainage in northeastern Madagascar. It can be distinguished from congeners by a longer snout (54.8–56.4% HL, vs. 47.1–54.3 in congeners) and faintly mottled dark gray coloration (vs. uniform brown, highly mottled dark gray and cream, or mottled brownish-gray). The following combination of characters further distinguishes Gogo atratus from congeners: dorsal-spine length 17.7–20.6% SL, pectoral-spine length 16.5–18.9% SL, length of adipose-fin base 23.6–27.8% SL, head width 17.8–18.9% SL, interorbital distance 28.9–30.5% HL, eye diameter 13.0–14.3% HL, unicuspid teeth, and straight dorsoposterior margin of dorsal fin.