Isadora Moon is half fairy and half vampire. All Unique.
In "Isadora Moon's Mermaid Adventure," (S2E1) Isadora and her family go on vacation and she accidentally loses her dad's prized comb. While under the sea searching for the comb, she meets a mermaid named Adelina and shapeshifts into a mermaid herself to continue the search. Another episode, "Mermaid Sleepover," (S2E4) features Isadora attending a sleepover at the Mermaid Palace with Princess Delphina.