A fish out of water

Meaning :

Someone who is in a situation they are unsuited to.

Origin :

This metaphor is quite old. Chaucer used a version of it in The Canterbury Tales : Prologue:

...a monk, when he is cloisterless;

is like to a fish that is waterless

The earliest reference that I can find to the present day wording of the phrase is in Samuel Purchas`s Pilgrimage, 1613:

"The Arabians out of the desarts are as Fishes out of the Water."