

Sibling Rivalry: With her younger sister, Kim.

Shrinking Violet: Unlike her more confident friends Rikki and Emma, Cleo tends to be quite shy.Nice Job Breaking It, Hero: Charlotte probably wouldn't have gone over the edge if Cleo hadn't been so hostile to her.Naïve Everygirl: The most naive and insecure of the main girls.Making a Splash: her powers involve shaping water.Ironic Fear: Initially struggles with a fear of water.Cool Big Sis: She may get into arguments with Kim, but she loves her regardless.Meanwhile, Charlotte's only real "crime" is trying to make advances on an apparently single guy, as Cleo insists to her that they're "just friends." Then when Charlotte comes along, she gets jealous and angry whenever they hang out and do things, even at one point sabotaging a dinner to try and drive the two apart. Clingy Jealous Girl: In season two, Cleo breaks it off with Lewis, stating that she can't have a boyfriend.Ambiguously Brown: Has a bit of a deeper complexion that none of the rest of her family have.Her powers are manipulating the shape of water, including the ability to create more water out of an existing amount. Played by: Phoebe TonkinCleo Sertori is the brunette of the group and a bit awkward, but eventually becomes more outgoing. They revert back to human once they're dried off. Water-Triggered Change: The girls change from human to mermaid upon coming into contact with water, no matter the amount.In season 3, Rikki is still the butch, Idol Singer Dude Magnet Bella takes over the femme role, and Cleo becomes the neither.The first two seasons have sweet naive Cleo (femme), level-headed Emma (neither) and rebellious tomboy Rikki (butch).
H2O JUST ADD WATER SEASON 2 FULL
Congruent with their origin, the full moon can have weird effects on them if they see it (what effects depends on planetary alignments), and in one case, permanently increase their powers. They also have powers over water: one can freeze it at will, one can boil it at will, and the other controls it at will (also she can multiply it from a drop to a bucket).

