Feet by day, scales by night: As operating systems go, the locomotive options of the title mermaid in the tweener romantic comedy Aquamarine represent a definite upgrade over Daryl Hannah's more cumbersome machinery in Splash. That's more than can be said about the rest of this movie, a filmy pool of tropes and tchotchkes stereotypically associated with Girls of Today. When Aquamarine (perky-pretty Sara Paxton, her twinkly expressions perfected on the TV series Darcy's Wild Life) tumbles into the swimming pool of a Florida beach club during a storm, she's all tail. But after she's befriended by trustworthy 13-year-old best friends Claire (Emma Roberts, still answering to the description ''niece of Julia'') and Hailey (Joanna ''JoJo'' Levesque), she reveals her day legs and confides her mission: If she can convince her mythological father that would be Neptune, King of the Sea that earthly love is real (in three days), then she can get out of an arranged marriage to an unappealing merman. Aquamarine sets her sights on a cute lifeguard, Raymond (Jake McDorman), and it's still the same old story: Girl meets boy, girl hides fins for fear of rejection, boy can't understand why girl is acting so...fishy.
That's only half the deal in this floppy production, based on a novel by Alice Hoffman and directed in a pink-centric feature debut by Elizabeth Allen. Claire (the fearful one) and Hailey (the rebellious one) have their own girlsville issues. Plus, they're crushing on Raymond too. That everything gets worked out friendship affirmed, jokes made about silly magazine articles on reeling in a boy is as sure as the soundtrack's inclusion of a Mandy Moore song.
In such a well-behaved femme aquarium, I'm far more diverted by the antics of the designated Mean Girl, a conniving queen bee called Cecilia. Played with well-honed comic obnoxiousness by Gilmore Girls' Arielle Kebbel, Cecilia another lifeguard luster, who wants Raymond for her own boy toy slithers through her classic bitch role with cheerful sharkiness while Aquamarine flounders.