The Bubble Love of the Mermaid, Vol. 1 (manga)

Eight years ago, a red, scalelike mark—the sign of a monster—appeared on Asana Amamizu’s wrist, and her life hasn’t been the same since. Now sixteen years old, Asana does her best to blend in at the Yotsuru Girls’ Academy, hiding her true nature as a girl with mermaid’s blood. Then her classmates begin gossiping about their charming new language arts teacher, Sakuya Shigure: a handsome, pale, young man whom Asana assumes would have nothing to do with her. That is until an unexpected marriage proposal falls directly into her lap!

Can this little mermaid write her way out of a tragic tale…and into a story of true love?