HomeFish encyclopediaRay-finned fishesPricklefishes, Bigscales and GibberfishesBigscale fishes or ridgeheadsNordenskjold's bigscale Nordenskjold's bigscale (Sio nordenskjoldii) Scientific name: Sio nordenskjoldii L?nnberg, 1905 The Nordenskjold's bigscale (Sio nordenskjoldii) is a marine fish of the family Melamphaidae. BiologyDorsal spines (total): 3; Dorsal soft rays (total): 9; Anal spines: 1; Anal soft rays: 8 - 9Source: FishBase, licensed CC BY-NC 4.0. Species factsScientific nameSio nordenskjoldiiFamilyMelamphaidae (Bigscale fishes or ridgeheads)OrderStephanoberyciformes (Pricklefishes, Bigscales and Gibberfishes)ClassActinopterygii (Ray-finned fishes)Maximum length12.3Depth range200–3000 m (656–9843 ft)EnvironmentMarine; bathypelagic; depth range 200 - 3000 mClimateDeep-waterDistributionAtlantic, Indian and Pacific: south of 20?S. A single specimen was recorded from the Eastern Central Pacific. Record from the North Pacific (Moss, 1962) is in error.Conservation status (IUCN)Not EvaluatedThreat to humansHarmlessUsesFisheries: minor commercial SourcesTaxonomy, distribution and biology data: FishBase (Froese, R. and D. Pauly, eds.), licensed CC BY-NC 4.0.Last updated 27 September 2026