Lethrinus mahsena, common names the sky emperor, mahsena emperor, and cutthroat emperor, is a species of emperor fish. It grows to 65 cm in length, but is commonly found at 35 to 45 cm. This fish may be yellow to greenish-blue or olive-grey, becoming paler toward the belly. It is a non-migratory, reef-associated fish that has a high commercial value.