The phrase "fish out of water" is an idiomatic expression that means someone who is in a strange or unfamiliar environment, situation or circumstance. It refers to being out of one's element and experiencing discomfort or difficulty as a result. The phrase originated from the fact that fish cannot survive outside of their natural habitat such as water, so when taken out of it they struggle to breathe and survive. In a figurative sense, this means someone who is not suited for a particular situation or lacks the necessary skills to cope with it.