HomeFish encyclopediaRay-finned fishesSmeltsBarreleyes or spookfishesBarreleye Barreleye (Macropinna microstoma) Scientific name: Macropinna microstoma Chapman, 1939 The Barreleye (Macropinna microstoma) is a marine fish of the family Opisthoproctidae. Native range: North Pacific, Bering Sea to Japan, and Baja California, Mexico. BiologyDorsal spines (total): 0; Dorsal soft rays (total): 11; Anal spines: 0; Anal soft rays: 14. This species' most striking feature is the transparent, cowl-like shield that covers the top of the head, and its prominent tubular eyes within. The shield is a tough, flexible integument that attaches to the dorsal and medial scales behind the head, and to the broad, transparent subocular bones that protect the eyes laterally. The fluid-field chamber found beneath the shield surrounds and protects the eyes with vivid green lenses. The tubular eyes of this fish can look forward as well as upward (with maximum arc of rotation observed about 75 degrees). The morphology of the eyes apparently allow at least two feeding modes: (1) with body horizontal and with eyes directed upward, it can spot food against lighted waters above, it pivots its body to bring the mouth up for ingestion while eyes are locked on target, rotating from dorsal to rostral relative to the body; and (2) withSource: FishBase, licensed CC BY-NC 4.0. Species factsScientific nameMacropinna microstomaFamilyOpisthoproctidae (Barreleyes or spookfishes)OrderOsmeriformes (Smelts)ClassActinopterygii (Ray-finned fishes)Maximum length15.0Depth range16–1015 m (52–3330 ft)EnvironmentMarine; bathypelagic; depth range 16 - 1015 mClimateDeep-waterDistributionNorth Pacific: Bering Sea to Japan, and Baja California, Mexico.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