Jarvis was seen by a casting agent working for director Andrea Arnold, and was cast in her film "Fish Tank", following a successful audition. She played Mia, a troublesome and aggressive 15-year-old girl from an underclass family, passionate about dance. The film was in the running for the Palme d'Or at the 62nd Cannes Film Festival, winning the Jury Prize. Jarvis won the British Independent Film Awards for her role.