a fish doesn't know it's in water

• metaphors for the idea of someone being unaware of their environment due to a lack of external perspective:

1. "A fish doesn't know it's in water."
2. "Can't see the forest for the trees."
3. "The frog in the well knows nothing of the great ocean." (Chinese proverb)
4. "Living in a bubble."
5. "An ant can't comprehend the mountain."
6. "To a hammer, everything looks like a nail."

• These metaphors illustrate the concept of being so immersed in one's own environment or perspective that one is unaware of larger contexts or differing viewpoints.