Translated literally, the idiom 井底之蛙 means “a frog at the bottom of a well.” Typically, the idiom is employed in the context of describing mindsets and outlooks of individuals, mostly naïve ones.
井底: bottom of a well
蛙: frog
There once lived a frog at the bottom of a well. He enjoyed his life in this well very much and felt very powerful as he was, well, the only resident of that well. To the frog, however, being the sole resident equaled absolute power.
So one day, this sea turtle is passing by the well. Feeling incredibly confident and ready to show off his incredible power, the frog jumps out and says, “Why don’t you come here often? Look at how wonderful my abode is. When I’m happy, I can sit on the edges of the well and jump around. When I’m tired, I just go back into the well and go to sleep. I can play with the water and with the mud at the same time. My well is the definition of pleasure.”
The frog’s words had a profound impact on the sea turtle, so it decided to explore. Peering over the walls of the well, the sea turtle merely saw a hole with water in it. It proceeded to tell the frog, “Have you seen the sea before? The oceans are incredibly big, bigger than this well of yours and deeper than this well of yours. When there are droughts on land, the ocean is still full of water. When there are floods on land, the ocean is still full of water. Unlike your well, the ocean is not affected by floods and droughts. Living in the sea, not in your well, is the definition of pleasure!”