Here's what www.netflix.com says:
Mega Piranha 2010 NR 90 minutes
Former pop princess Tiffany co-stars in this nerve-wracking thriller about gigantic, mutant piranhas who are irradiated in the Amazon River by well-meaning scientists in a misguided attempt to revive the local piranha population.
This movie was pretty good. It had some pretty crazy stuff too! It was a good, not too bloody scary movie.