The exact meaning of the fly varies among different cultures, but the fly is often symbolic with death, rotting, pestilence and upcoming change. In nature, flies are decomposers and feed on dead, decaying animals, fecal matter and trash. This is one of the reason that flies are often associated with death or sickness.
Some cultures believe that having a fly cross someone's path is indicative that sudden changes in the person's thoughts, emotions or life are coming. If a fly is present in someone's dreams, the exact meaning depends on what the fly is doing. A fly that is eating meat is symbolic of the death and life cycles. When flies eat something sweet, this indicates that abundance and prosperity are going to enter the dreamer's life.