Big fish in a small pond

Meaning

Someone who is important or successful in a small environment but would not be particularly special if they moved to a larger or more competitive sphere.

Observational, slightly snarky

Used in a sentence

• He is a big fish in a small pond in this town, but he would struggle in a big city firm.
• She enjoys being a big fish in a small pond at her local community theater.
• Sometimes you have to leave your small pond if you want to grow past being a big fish.