Sailor Aluminum Siren is the second of the animamates (after Sailor Iron Mouse). Before she was taken over by the evil influence of Galaxia she was known as Sailor Mermaid, the protector of her respective planet, Planet Mermaid. In her Senshi form she has her trademark long flowing wavy light blue hair, criss-crossing purple bands on her face that are connected by a little golden star, winged earrings (also with stars), an outfit that is somewhat of a cape dress with criss-crossing purple ribbons tying it , garter belts that hold up her flashy purple tights, high heels with the same criss-crossing ribbons as her dress that go almost to her knees, and her two bracelets they are gold, the left one has a green stone in it and the right one has a purple stone. Siren is also able to attack with her long blue hair! Siren's attitude seems self assured most of the time and when she thinks she is right she is very stubborn.

As Reiko Aya she wears a light pink lavendar colored buisness suit, a pink pillbox hat, cat eye sunglasses, and as an accessory usually a bag of potato chips or some other snack is seen in her possesion.