HomeFish encyclopediaRay-finned fishesScorpionfishes and FlatheadsSculpinsLongfin Irish lord Longfin Irish lord (Hemilepidotus zapus) Scientific name: Hemilepidotus zapus Gilbert & Burke, 1912 The Longfin Irish lord (Hemilepidotus zapus) is a marine fish of the family Cottidae. In the aquarium it needs water at 0–4°C (32–39°F). Native range: North Pacific, northern Kuril Islands, Bering Sea and Aleutian Islands, Alaska. Longfin Irish lord care at a glanceTemperature0–4°C (32–39°F) Species factsScientific nameHemilepidotus zapusFamilyCottidae (Sculpins)OrderScorpaeniformes (Scorpionfishes and Flatheads)ClassActinopterygii (Ray-finned fishes)Maximum length26.0Common length17.6Depth range61–530 m (200–1739 ft)EnvironmentMarine; demersal; depth range 61 - 530 m, usually 100 - 250 mClimatePolarDistributionNorth Pacific: northern Kuril Islands, Bering Sea and Aleutian Islands, Alaska.Conservation status (IUCN)Not EvaluatedThreat to humansHarmlessUsesFisheries:ResilienceLow, minimum population doubling time 4.5 - 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