Millet butterflyfish stripe runs from above the eye to the base of the operculum, and there is a large black patch on the caudal peduncle. This fish is endemic to the Hawaiian Islands and the Johnston Atoll, and is found down to depths of at least . Its habitats include coastal fringing reefs, outer reefs and lagoons. The millet butterflyfish is a schooling species found in mid-water that feeds on zooplankton. It also feeds opportunistically on polychaete worms and other small invertebrates on the seabed. Food is drawn into the mouth by rapid suction. It does not seem to be territorial but
Blob sculpin flap that covers the gills), the branchiostegal membranes are fused to the isthmus (the fleshy projection separating the gill openings), and there are many small cirri (fleshy threads) scattered over the head and body. The operculum is poorly ossified and is covered by a gelatinous layer. Behind the head, the body tapers rapidly to the caudal peduncle and there is a gelatinous layer between the skin and the muscle. The dorsal fin has eight spines and nineteen to twenty soft rays, and the anal fin has no spines and twelve to fourteen soft rays. The pectoral fins are broad and