Barred knifejaw is a coastal reef fish with fused, beaklike teeth for crushing sea urchins and barnacles. Young fish have a silvery body with bold black bars that fade as they grow. Some reached the U.S. West Coast on debris from the 2011 Japan tsunami, but no established wild population has been documented there.

Appearance

Appearance
Young fish have a deep, silvery body crossed by bold black bars. The bars fade as the fish grows, the mouth area darkens, and adults may reach about 31 in (80 cm).

Look-alikes

StripeyMicrocanthus strigatus

A stripey is yellowish with narrower, slanted dark stripes and usually stays under about 6.5 in (16 cm). A young barred knifejaw has broader, straighter black bars and develops a heavy beaklike mouth.

Why they get mixed upBoth are deep-bodied reef fish with dark bars and both occur in Hawaii.

Pacific spadefishChaetodipterus zonatus

On the California coast, a young Pacific spadefish has five or six dark bars, some shorter than others. A young barred knifejaw has seven bars of more even length and rounder rear dorsal and anal fins.

Why they get mixed upYoung fish of both species are deep-bodied and striped.

Where it lives

Typical habitats
  • coastal rocky reefs
  • shallow kelp and seaweed areas
Range
It lives naturally in the Pacific around East Asia and Hawaii. Fish reached Washington, Oregon, and California from 2013 to 2015 on tsunami debris; no established West Coast population is documented.
Preferred conditions
Juveniles travel with and floating debris. Larger fish settle around rocky reefs.

Behavior

Diet
The fused, beaklike teeth crush hard prey such as barnacles, sea urchins, and snails. Younger fish also take small and other tiny drifting animals.
Social life
Young fish may gather around drifting seaweed. Adults live close to rocky bottoms.

Life cycle

Breeding season
In its native Japanese range, spawning occurs mainly from April through July.
Reproduction
Spawning takes place near the coast and may be repeated many times during one season.

Conservation

IUCN Red List
LCLeast ConcernLow risk of extinction

Culture and stories

Culture and stories
  • It is harvested, farmed, and pursued as a game fish in its native range.
12 sources
  1. iNaturalist Taxon API — Oplegnathus fasciatus
  2. 국립수산과학원 생물종 정보 — 돌돔
  3. FishBase — Oplegnathus fasciatus
  4. FishBase Ecology — Oplegnathus fasciatus
  5. 水産庁 — イシダイの生態特性
  6. 千葉県立中央博物館分館 海の生きもの観察ノート
  7. USGS Nonindigenous Aquatic Species — barred knifejaw
  8. FishBase — Microcanthus strigatus
  9. 부산광역시 수산자원연구소 — 돌돔
  10. Gyeongsang National University — juvenile Oplegnathus fasciatus diet
  11. NOAA — barred knifejaw and Pacific spadefish comparison
  12. 국립해양생물자원관 — 아홉동가리
Barred Knifejaw (Oplegnathus fasciatus) — identification, habitat & look-alikes | Moeyo