Leo Lionni, the American author, is a gifted and humanistic writer of children's literature. His children's picture books Fish is Fish telling a very interesting story. Lionni has always been good at combining beautiful pictures, clear language, and pure thinking. He clearly proved such a truth: a little fish can't go beyond the limit of breathing in the water to understand the world. In addition, it can also make children realize that life is full of meaning. Even for a small fish in a small pond, we should learn to know ourselves. By telling the story of little fish, this book can let children learn to know and accept themselves, and grasp the sails of the ship of life.