Piranha is a water based horror movie based on the earlier and more successful Jaws series of movies; unlike Jaws, which featured a single shark attacking innocent teens in the ocean a genetically modified school of piranha are the monsters in Piranha. The movie was produced by Roger Corman and created by a team of people who had earlier worked for the legendary American B Movie producer, including writer John Sayles and director Joe Dante.
Although the plot to Piranha is quite complicated it takes a second place to the shocks and gore of the attacking school of fish. The movie opens with two teenagers swimming in what they believe to be a disused swimming pool on an old army base, while swimming the pair are dragged under the water and killed by what we later learn to be the piranha. A dogged insurance investigator is sent to find the missing teens in the Lost River Lake community and finds the disused army research base. After draining the pool the investigator, Maggie McKeown is told by a doctor from the base she has released the modified piranha from the pool into the surrounding waters; at the bottom of the drained pool Maggie finds the skeletons of the two teenagers.
The plot of the movie progresses with revelations about an Army research center designed to create a genetically modified school of piranha that would be released in Vietnam to slow the movements of the Vietnamese militia moving along riverbeds. A large number of deaths then take place before the piranha escape. The former head of the Piranha research program, code named Operation: Razorteeth is later seen attempting to calm a worried public on TV and radio.
John Sayles wrote Piranha and would later write, direct and act in his own films, including Eight Men Out, Lone Star and Apollo 13. The movie was directed by Joe Dante, who would later find critical and commercial success with another horror based series of movies, Gremlins and Gremlins 2. Piranha spawned sequels and a large number of remakes. A Roger Corman produced remake was produced in 1995 and broadcast on TV without a theatrical release.