Piranha

While searching for missing teenagers, novice skip tracer Maggie McKeown (Heather Menzies) and local town boozer Paul Grogan (Bradford Dillman) stumble upon a top-secret Army laboratory conducting genetic research on piranha fish for the purpose of developing biological warfare. When the deadly eating machines are accidently released from the compound, they are soon headed downstream and consuming everything, and anything, in their path. (official distributor synopsis)