Amy is the 'leader' of the group, for she was the first one out of Brenna and Kelsey to become a mermaid. Her first tail was pink, but when she reentered the magic pool, it turned light blue. Later in the series, she accidentally drinks a potion that turns her tail dark blue, where it remains now. Amy has always dreamed of having a regular bond with her sister, but she might never get to, because Tess always has a plan to reveal the girls' secret. Amy was friends with Kelsey first, but when Brenna became a mermaid she started hanging out with her more and more, resulting in Kelsey getting jealous. Eventually, they all were mermaids, and Kelsey's jealousy faded. Amy's power is controlling water; although in the beginning she possessed all the powers (Earth, Air, Fire, and Water). Whenever the others girls came along, Brenna got fire; Kelsey got air. And Blaire's mom, Terra, got Earth, hence the name 'Terra', meaning, well, Earth. Amy and the other girls believe this is because there can only be four mermaids in a century (listed in order): Terra, Amy, Brenna, and Kelsey.
Amy begins as a normal girl living in Florida, but when she goes out for an ocean swim, a big storm blows in. Seeing a cave in the distance, Amy decides to take shelter in it. Abruptly, a waterfall begins pouring down onto her. The next day, she spills water on herself and transforms into a mermaid with a pink tail.
Amy keeps her secret as best she can from both her sister Tess and friend Brenna, until Brenna follows her to the Sunset Waterfall and transforms, giving her someone to relate to.
Things get complicated, since Amy's birthday and Christmas are both coming up. Amy tells Tess the secret, but she loses her memory. Amy's old friend Kelsey finds out about the secret and Amy's tail changes to blue. Then,when Kelsey is out trying to find the scrapbook, she becomes a mermaid with a green tail.
Amy starts to get used of the fact that Kelsey is a mermaid, and not having three powers. Her tail changes to indigo, she starts wearing braces and the new girl Blaire Harris. But, most of all, Amy must indure that things just arent the same anymore. Espacially, when a Huanted memory comes back..
In the episode "In The Wake," it's revealed that she has a cousin named Andy, and that got stuck on the roof once.
In the Episode "Freezer Burn", we learn that Amy has an older sister named Tess, and she is a bully to her.