After Seeing the Barrage, He Robbed the Little Shark.

Are There Any Sharks Who Have Gender-Neutralized into Boys Because They Fell in Love with the Female Protagonist?

Is there a shark who becomes a boy because he falls in love with the female protagonist? I've been wanting to watch this kind of thing recently, but I haven't found anything similar. I remember seeing it in a fast-traveling article a long time ago, but I forgot the name.