This is a mermaid who can change into a human for a short amount of time. To do that, she must get permission from one of the ocean's fish, by way of a kiss. However, the fish love her too much to let her go, even for a short while. Only the Flying Fish understands her desire, because he sees the world as he flies out of the water, even if it's only for a brief second, and he thinks it's beautiful, so he always grants her a kiss so she can change :-)