HomeFish encyclopediaRay-finned fishesSawbelliesSlimeheadsSlender roughy Slender roughy (Optivus elongatus) Scientific name: Optivus elongatus G?nther, 1859 The Slender roughy (Optivus elongatus) is a marine fish of the family Trachichthyidae. Native range: Southwestern Pacific, Restricted to New Zealand. BiologyNocturnally active; inhabits cracks and crevices during the day. Feeds on small mobile benthic organisms, by drifting up to its prey and swallowing it whole with a sideways snap of the large extensible mouth.Source: FishBase, licensed CC BY-NC 4.0. Species factsScientific nameOptivus elongatusFamilyTrachichthyidae (Slimeheads)OrderBeryciformes (Sawbellies)ClassActinopterygii (Ray-finned fishes)Maximum length72.0EnvironmentMarine; reef-associatedClimateDeep-waterDistributionSouthwestern Pacific: Restricted to New Zealand.Conservation status (IUCN)Not EvaluatedThreat to humansHarmlessUsesFisheries: of no interestResilienceVery Low, minimum population doubling time more than 14 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