Pearl Swirl Mermaid This tween mermaid costume includes the long fitted dress, glovelette, starfish w/pearls and choker. The mermaid costume comes in kids and tween sizes X-Large, Large. A sheer puffed hem creates the cute fishtail on this tween mermaid costume. This mermaid costume is an officially licensed Strangeling costume. The shoes and headpiece are not included with this mermaid costume for tween girls.