HomeFish encyclopediaRay-finned fishesPerch-like fishJawfishesHalfnaked jawfish Halfnaked jawfish (Opistognathus seminudus) Scientific name: Opistognathus seminudus Smith-Vaniz, 2004 The Halfnaked jawfish (Opistognathus seminudus) is a marine fish of the family Opistognathidae. Native range: Western Pacific, Australia. BiologyDorsal spines (total): 10 - 11; Dorsal soft rays (total): 14-16; Anal spines: 2; Anal soft rays: 14 - 15; Vertebrae: 28 - 29. This species is distinguished by the following set of characters: D XI (exceptionally X), 14-16; about 28-36 oblique scale rows in longitudinal series on body; no scales anterolaterally forward of verticals from ultimate spine to 2nd segmented dorsal-fin ray; conspicuous ocellus between spines 2-5 of dorsal fin; 1-3 vomerine teeth.Source: FishBase, licensed CC BY-NC 4.0. Species factsScientific nameOpistognathus seminudusFamilyOpistognathidae (Jawfishes)OrderPerciformes (Perch-like fish)ClassActinopterygii (Ray-finned fishes)Maximum length8.6Depth range0–22 m (0–72 ft)EnvironmentMarine; demersal; depth range 0 - 22 mClimateTropicalDistributionWestern Pacific: Australia.Conservation status (IUCN)Not EvaluatedThreat to humansHarmless SourcesTaxonomy, distribution and biology data: FishBase (Froese, R. and D. Pauly, eds.), licensed CC BY-NC 4.0.Last updated 27 September 2026