Fish Tank walks well-trod ground, but it’s still riveting from start to finish. Director Andrea Arnold proves that her debut feature, Red Road, was no fluke — she has a great eye for urban landscapes and a real way with actors. Set in Essex County, England, Fish Tank is all about Mia, an obstreperous 15-year-old with a stack of chips on her shoulder and a way with hip-hop dance moves. The central performance by Katie Jarvis is the bright ball of energy around which the whole film revolves, and she’s pretty terrific — she gives an easy, naturalistic performance that’s pure teenage girl, whether she’s bloodying the collective nose of her peer group or (symbol alert) pounding the hell out of a padlock that keeps a friendly gray horse chained up on one of the neighborhood’s desolate, nearly empty lots that smells of young men and menace.