Bedotia alveyi, a new species of Malagasy rainbowfish, is described from the lower reaches of the Antainambalana and Vohimaro rivers and their tributaries near the village of Maroansetra in the Makira Forest Protected Area, northeastern Madagascar. The new species is distinguished from congeners by the presence of a distinctive crescent-shaped to semicircular spangle on the posterior half of many opercular and flank scales, which creates iridescent golden (occasionally whitish to bluish) highlights. Additional unique pigmentation pattern features include a dark midlateral stripe interrupted by sparse lateral blotching and rust-red caudal-fin lobes. Bedotia alveyi is one of several new species that were collected during a brief expedition into the Makira Forest region in 2003. The Makira Forest was designated a Malagasy protected area in December of 2005.