This is a story by Tezuka Osamu, an animator who was called "God of animation".
It is about a creative boy who finds a fish and believes it's a mermaid, and takes place in a country which restricts imagination. The boy finds a fish nearby the ocean, and it turns into a mermaid. The mermaid and the boy enjoys by playing music. Then the boy takes the mermaid to his house, and show the adults. Soon the adults took the boy away, enforcing him to stop make-believing. At the end, he no longer could imagine what the mermaid looked like. However, after he was released, he goes to the ocean again with the fish, and he decides to play with the mermaid, letting himself swim along to the offshore.
I think this story tries to tell that adults prohibits the freedom to imagine, and that you can be more creative.
