HomeFish encyclopediaRay-finned fishesPerch-like fishMackerels, tunas, bonitosSlender tuna Slender tuna (Allothunnus fallai) Scientific name: Allothunnus fallai Serventy, 1948 The Slender tuna (Allothunnus fallai) is a marine fish of the family Scombridae. Native range: Southern Ocean, circumglobal. One individual taken in Los Angeles Harbor. BiologyDorsal spines (total): 15 - 18; Dorsal soft rays (total): 12-13; Anal spines: 0; Anal soft rays: 13 - 14; Vertebrae: 40. Interpelvic process small and bifid. Body naked ventrally behind the long anterior corselet. Dorsal half of body to lateral line covered with scales. Swim bladder absent. The back is bluish, turning to deep purple or almost black on the head; the belly is white, without stripes or spots; the pectoral and pelvic fins purple, their inner sides black.Source: FishBase, licensed CC BY-NC 4.0. Species factsScientific nameAllothunnus fallaiFamilyScombridae (Mackerels, tunas, bonitos)OrderPerciformes (Perch-like fish)ClassActinopterygii (Ray-finned fishes)Maximum length105Common length86.0EnvironmentMarine; pelagic-oceanic; oceanodromousClimateSubtropicalDistributionSouthern Ocean: circumglobal. One individual taken in Los Angeles Harbor.Conservation status (IUCN)Not EvaluatedThreat to humansHarmlessUsesFisheries: minor commercialResilienceMedium, minimum population doubling time 1.4 - 4.4 years (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