Ayu Sweetfish (Plecoglossus altivelis) — identification, habitat & look-alikes

Ayu Sweetfish is an East Asian fish that hatches in rivers, spends its early life near the coast, and returns upstream in spring to feed. Past attempts to introduce it to the United States did not establish wild populations. It is also called sweetfish.

Appearance

Appearance: It is a slender, silvery fish with a darker back.

Where it lives

Typical habitats: East Asian rivers
Coastal waters
Range: It is native to the western Pacific coast of Asia, including Japan and Korea. U.S. attempts to establish it in California and Hawaii failed.
Migration: The migratory form moves from rivers to coastal water as a hatchling and returns to rivers the following spring.

Behavior

Diet: In rivers, it scrapes algae from rocks. Young fish near the coast feed on .
Social life: Adults may defend patches of algae-covered stones.

Life cycle

Breeding season: Across its East Asian range, spawning occurs in fall, with timing varying by region.
Nest: Adults lay eggs in shallow gravelly reaches of rivers.
Lifespan: Most adults die after their first spawning season.

Conservation

IUCN Red List: DDData DeficientNot enough data yet to assess

Culture and stories

Culture and stories: Ayu is a valued food and fishing species in Japan.

11 sources