HomeFish encyclopediaRay-finned fishesPerch-like fishSpadefishes, batfishes and scatsThreadfin scat Threadfin scat (Rhinoprenes pentanemus) Scientific name: Rhinoprenes pentanemus Munro, 1964 The Threadfin scat (Rhinoprenes pentanemus) is a brackish-water fish of the family Ephippidae. Native range: Western Pacific, Papua New Guinea to northern Australia. BiologyDorsal spines (total): 8; Dorsal soft rays (total): 19-20; Anal spines: 3; Anal soft rays: 16 - 17. Body deep and compressed, quadrangular in outline. Mouth small and inferior. Second dorsal spine, fourth pectoral ray, and first pelvic ray greatly prolonged into free filaments which reach tail base or beyond. First dorsal-fin spine, fourth pectoral-fin ray, and first pelvic-fin ray greatly elongated filaments, reaching to or beyond vertical line at rear end of dorsal-and anal-fin bases. Head naked. Mouth inferior, the snout and upper jaw projecting in front of lower jaw (Ref 43039).Source: FishBase, licensed CC BY-NC 4.0. Species factsScientific nameRhinoprenes pentanemusFamilyEphippidae (Spadefishes, batfishes and scats)OrderPerciformes (Perch-like fish)ClassActinopterygii (Ray-finned fishes)Maximum length15.0EnvironmentMarine; brackish; demersalClimateTropicalDistributionWestern Pacific: Papua New Guinea to northern Australia.Conservation status (IUCN)Not EvaluatedThreat to humansHarmlessUsesFisheries: of no interestResilienceHigh, minimum population doubling time less than 15 months (Preliminary K or Fecundity.) SourcesTaxonomy, distribution and biology data: FishBase (Froese, R. and D. Pauly, eds.), licensed CC BY-NC 4.0.Last updated 27 September 2026