A big fish in a small pond is someone who is important and influential in a small place or organization.
Examples of use:
1. You're not so special: you're just a big fish in a small pond!
2. I was a big fish in a small pond where I used to work; but in my new job nobody even knows my name.
3. As the village doctor he was a big fish in a small pond.
More fish idioms:
a big fish - a very important person
a small fish – an unimportant person
a queer fish – a strange or odd person
a cold fish – a cold person, showing no feelings or emotion
Do you know someone who is a big fish in a small pond? Can you write a sentence about that person?
Image © Mike Johnston