What does As nervous as a fish out of water means?

The phrase "as nervous as a fish out of water" describes someone who is extremely anxious or uncomfortable in their current situation. Just as a fish struggles and feels vulnerable when removed from its natural aquatic environment, a person in an unfamiliar or challenging context may feel similarly out of place and uneasy. This idiom emphasizes the feelings of disorientation and stress that can arise when one is in an unfamiliar or hostile environment.