A new species of the sand eel genus Bascanichthys (Anguilliformes: Ophichthidae) is described from specimens found inside the stomachs of mature female numbfish Narcine bancroftii. These rays were collected as bycatch in local fisheries, using beach seines in shallow waters (5 to 10 m) in Gaira Bay (Santa Marta, Colombian Caribbean). Bascanichthys gaira n.sp., is described from three specimens and can be distinguished from other species of the genus by its minute pectoral-fin base (12.3- 24.7% of gill-opening length) and its vertebral number (189).