(idiomatic) "a fish who's found water" → In one's element, a duck to water.

lip service; promising but empty talk / skillful completion of a task

a black-backed wagtail (Motacilla alba lugens)

pretty, beautiful

pretty, gorgeous, beautiful / clear, clean, pure / clean, not dirty / tidy, neat, everything put away / fair, impartial, of clear conscience

Alternative form of 白河夜船 (shirakawa yofune)

being fast asleep, dead to the world when sleeping / pretending to know everything, a know-it-all manner

fish

Alternative spelling of 雷魚

a fish