A fish out of water
Definition 1 of 1
Pro Tip 1/3Emotional Charge
This phrase often implies a sense of anxiety or discomfort. 
Attending the advanced calculus class, she felt like a fish out of water.
Pro Tip 2/3Figurative Use
Remember, it's used metaphorically to describe someone's feeling, not a real situation. 
At the formal dinner, Joe, in his casual clothes, felt like a fish out of water.
Pro Tip 3/3Not Literal
We don't use this phrase to describe actual fish or water. 
During the quiz show, with all the tricky questions, I was like a fish out of water.