Rikki Chadwick is the mermaid with light blonde hair on H2O, Just Add Water. My daughter found this show on Netflix, and we have met many fans looking for tails.
Rikki lives with her dad, and is the most direct girl of the three main characters- sometimes she is sarcastic and she is a bit of a risk taker.
Rikki’s hair is light blonde, she has blue eyes, and her tail is a gold/yellow/orange with matching top, just like her friends.
(I got the photo from h20wikia.com, which is a wealth of information for any fan!)