Mia (Katie Jarvis) is a feisty 15 year old who lives in a working-class complex in Essex, England, with her promiscuous mother Joanne (Kierston Wareing) and younger sister Tyler (Rebecca Griffith). She doesn't get along with her mother and their face time usually consists of yelling at each other. Mia is an angry and unhappy adolescent who desperately yearns to be free, yet she has few clues how to achieve that desired state of bliss. The closest she comes to it is when she repeatedly tries to rescue a horse tied up in a junkyard. It is there she meets and is befriended by Billy (Harry Treadaway) but she feels ill-equipped to start a romantic relationship with him.

Mia is very curious about sex and finds herself intrigued by Connor (Michael Fassbender), her mother's latest boyfriend. After moving in with them, he shows an interest in her that no one else equals. Mia doesn't know how to read what is going on between them and in the end, she learns how mysterious sexuality can be for both adults and teenagers. The best way she finds for dealing with her conflicts at home with her mother and foul-mouthed sister, as well as the complications of sex, is her love of improvised dance. Mia watches countless hip-hop videos and practices on her own in an abandoned apartment. She dreams that her creativity will carry her out of Essex and to better days.

Fish Tank is directed by Andrea Arnold who won the Prix du Jury at the 2006 Cannes Festival for her debut picture Red Road. Whereas that film dealt with a wide range of issues including privacy in an age of technology, sexual power, and urban loneliness, Fish Tank is more focused on the coming-of-age misadventures of a rebellious and confused teenage girl. She is not a very likeable character yet Arnold manages to stay with her on her journey to find a place for herself to thrive and to bloom.

Special features on the DVD include three short films by director Andrea Arnold: Milk (1998), Dog (2001), and the Oscar-winning Wasp (2003); new video interview with actor Kierston Wareing; audio conversation with actor Michael Fassbender from 2009 audition footage; stills gallery by set photographer Holly Horner; original theatrical trailer; plus: a booklet featuring an essay by film scholar Ian Christie.