To dream of a piranha represents an issue or problem that “eats away” or destroys everything it’s exposed to. People or situations that could ruin or negatively influence all that you have. Areas of your life that may be totally lost because of a single failure or embarrassment.
Example: A woman once dreamed of a piranha trying to eat her. In real life she feared embarrassing information being revealed about her that could destroy her relationship and the life she’d built around it.