Fish Tank starts as a familiar coming of age tale, but in the middle of the third act bucks convention dramatically. 15 year-old Mia comes from a broken home and lives with her mother and her younger sister, perpetually dishing streams of expletives and insults in their general direction. Things aren't much better outside these four walls, as she bullies other girls and dabbles in illegalities. She harbors secret aspirations of becoming a hip-hop dancer, but all in all, her life sucks, and she knows it.
Everything changes when her mother begins dating the charming Connor (Michael Fassbender). He treats her kindly, supports her dancing, and is everything her life is bereft of. Unsurprisingly, she crushes hard. Her crush is the familiar teenage variety, born from frustration and jealousy. It is all-consuming. She watches him longingly from afar, visits him at work, takes interest in his interests. Everything feels innocuous enough, and you wait for the scene when she awkwardly acts on her feelings and is rebuffed. I'm not going to spoil the movie for you, but that does not happen. The gripping third act is a complete deconstruction of this kind of film, and offers no easy answers.
Director Andrea Arnold does a lot with the typical mumblecore, cinema-verite' style that is popular these days, but stretches it over a tense story arc to keep it from feeling slight and pointless. Many shots are from hand-held cameras, offering Mia's viewpoint from her bed or through a window, observing her subjects from a distance with detached loneliness. You don't blame Mia for feeling attracted to the first person who treats her with dignity, and despite her callous behavior, you pull for her. Like the California Dreamin' cover that plays a large role in the film, Mia's life is quite the winter's day. She is not without her own California dreams, but without knowing the rules of adult life, she chases them in unfortunate ways.