Rikki Chadwick

Season One
Season Three
Rikki Chadwick lives with her dad. She used to date Zane. Rikki is a tough girl but seems to really enjoy being a mermaid. Her power is to heat water and she used to work at Rikki's cafe.

Emma Gilbert

Season 1
Season 2
Emma Gilbert has the power to freeze water. She lives with her parents and her brother, Elliot Gilbert, who plays soccer. Emma used to swim competitively but was forced to give it up on the magical night when she became a mermaid. She is almost always the top of her class. The locket she owns was Ms. Louise Chatam's and has a white gem. Before her last year of high school, Emma left Australia to travel the world with her family.

Cleo Sertori

Seson 1
Seson 3
Cleo Sertori
Cleo can be very insecure. she is also quite clumsy, but she is one of the kindest in her group of friends. Her father is Don Sertori and her stepmother is Samantha Sertori. Cleo's sister, Kim Sertori, has a knack for getting Cleo in trouble.
Cleo does not like fishing, but loves her fish, Hector in particular. Before becoming a mermaid, Cleo was afraid of water and could not swim. Her power is to move and control water. The locket that she owns was Gracie's. It has a blue gem on it.