HomeFish encyclopediaRay-finned fishesPerch-like fishRoundheadsThreadfin longfin Threadfin longfin (Plesiops gracilis) Scientific name: Plesiops gracilis Mooi & Randall, 1991 The Threadfin longfin (Plesiops gracilis) is a marine fish of the family Plesiopidae. Native range: Western Pacific, Indo-Australian Archipelago. Closely related to Plesiops cephalotaenia from the Philippines and the Ryukyu Islands to the Solomon Islands. BiologyDorsal spines (total): 11 - 12; Dorsal soft rays (total): 7-8; Anal spines: 3; Anal soft rays: 8. Has nine pale stripes on the body.Source: FishBase, licensed CC BY-NC 4.0. Species factsScientific namePlesiops gracilisFamilyPlesiopidae (Roundheads)OrderPerciformes (Perch-like fish)ClassActinopterygii (Ray-finned fishes)Maximum length7.0Depth range2–16 m (7–52 ft)EnvironmentMarine; reef-associated; depth range 2 - 16 mClimateTropicalDistributionWestern Pacific: Indo-Australian Archipelago. Closely related to Plesiops cephalotaenia from the Philippines and the Ryukyu Islands to the Solomon Islands.Conservation status (IUCN)Not EvaluatedThreat to humansHarmlessResilienceHigh, 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