- English Name : Oil fish
- Local Name : Theyo mas
- Size : Max. 3 m
- Family : GEMPYLIDAE
- Order : Perciformes
- Distinctive Characters: First dorsal fin with 13-15 spines, second dorsal fin with 15-18 rays and 2 finlets. Anal fin with 15-18 rays and 2 finlets. Pectoral fin with 13-15 rays. Belly keeled, with dermal processes between pelvic fins and anus. Eye fairly large and round. Lateral line single and often obscure. Scales cycloid (smooth). No keels on caudal peduncle. Caudal fin broad and forked.
- Colour: Body uniformly violet or purplish or brown when alive. Dull brown after death.
- Habitat and Biology: Benthopelagic, mostly occurring on continental shelf and oceanic slope in depths of
100 to 700 m. Feeds on a wide variety of fishes, crustaceans and cephalopods. Distribution: Worldwide in warm waters. - Remarks: The specimen of Ruvettus pretiosus on which this record made was taken by gillnet from R. V. “Matha Hari�? about 30 miles east of Male�? on 16 March 1988.