Metamorphosis

Metamorphosis is the first episode of the first season and the first episode of the H2O: Just Add Water overall.

Synopsis
Emma and Cleo meet new girl, Rikki, and find themselves stuck on Mako Island where they are transformed intomermaids. As well as growing tails, the girls find they have powers over water.

Main

 * Cariba Heine as Rikki Chadwick
 * Claire Holt as Emma Gilbert
 * Phoebe Tonkin as Cleo Sertori
 * Angus McLaren as Lewis McCartney

Supporting

 * Burgess Abernethy as Zane Bennett
 * Jamie Timony as Nate
 * Cleo Massey as Kim Sertori
 * Ariu Lang Sio as Wilfred

Trivia

 * First Appearance of Cleo Sertori.
 * First Appearance of Rikki Chadwick.
 * First Appearance of Emma Gilbert.
 * First Appearance of Lewis McCartney.
 * First Appearance of Zane Bennett.
 * First Appearance of Kim Sertori.
 * First Appearance of Nate.
 * Cleo, Rikki and Emma became mermaids in this episode.
 * The Mako Island and the Moon Pool are seen for the first time.