An idiom meaning someone who is awkward or out of place because they are away from their usual environment — equivalent to 'a fish out of water.'
大学生になって都会に出たら、彼はまるで陸に上がった河童のようだった。
When he moved to the city for university, he was like a fish out of water.
新しい職場では専門用語が多く、最初のうちは陸に上がった河童だった。
There were many technical terms at the new workplace, and at first I felt like a fish out of water.
海外旅行で言葉が通じないと、誰でも陸に上がった河童の気分になる。
When you travel abroad and can't communicate, anyone can feel like a fish out of water.