Body elongate and slightly compressed, ventral side of body relatively flat. Snout shorter than eye diameter. Dorsal and anal fins situated posteriorly on body; origin of anal fin below second ray of dorsal fin. Pelvic fin long, its tip extended posteriorly beyond origin of anal fin. Pectoral fin greatly elongated, its length 60〜70% of SL; first ray of fin unbranched, other rays branched. Caudal fin deeply forked, lower lobe longer than the upper. No palatine teeth. Body dark blue dorsally, white ventrally; pectoral fin dusky with a pale basal triangle and a narrow white margin; dorsal, anal, and pelvic fins pale gray; caudal fin dusky.
Distribution:
Widely distributed in the tropical waters of the Atlantic Ocean.
Remarks:
The genus Hirundichthys is distinguishable from other flyingfish genera by the following points: the tip of pelvic fin extended posteriorly beyond the origin of anal fin, the number of rays in dorsal and anal fins differing by not more than 2 rays, and the origin of anal fin below the second ray of dorsal fin. (Matsuura)