FAQ for
Piranha Part Two: The Spawning (1981) Plus avec IMDbPro »

Not really. It contains none of the same characters, and it doesn't seem to be a continuation of the first film in any way. Although the implication at the end of the first movie was that the piranha had reached the ocean, in this film they are there because a military study has accidentally dropped a canister of the fish eggs into the ocean. Furthermore, athough it does involve genetically altered fish, they're not really even piranha. They're actually a gene-spliced version of the flying fish and the grunion.