(I don't own this picture. All Rights go to the owners.)

Name: Aqua Starlight
Age: Adult
Gender: Female
Species: Mermaid
Appearance: Has short blue hair with purple hairstreaks, light brown color eyes, light purple skin and a light blue mermaid tail.
Wears: A pink short puff sleeve shirt, an orange skirt tied around her waist, pink teardrop earrings, pink and light green striped armwarmers, a pink and light green striped satchel, a light green vest and a pink teardrop pendant.
Mermaid Popstar: An orange long sleeve shirt, a light green skirt tied around her waist, pink butterfly earrings, pink lace fingerless gloves and a pink butterfly pendant.
Personality: Kind, smart, caring, talented, brave, strong, creative, helpful, free spirited, shy sometimes, silly, clumsy sometimes
Crush: Patrick (Crush later Boyfriend)
Friends: Patrick, Sandy, Squidward (Sometimes), Mr Krabs, Karen, Kelly Daughter of Plankton and Karen
Enemies: Plankton, Squidward (Sometimes)
Family: Nova (Older Twin Sister)
Others: Works part-time at the Krusty Krab as a waitress and works as a Mermaid Popstar with her older twin sister Nova.

Sounds like Sarah Jeffery