noun
rainbow smelt
A species of smelt (Osmerus mordax dentex) found in northern Japan; the name literally means 'cucumber fish'.
北海道では、春にキュウリウオが川を遡上する。
In Hokkaido, rainbow smelt run up the rivers in spring.
The name キュウリウオ literally means 'cucumber fish', likely from the cucumber-like smell of fresh specimens.