Piranha 3D tries to do things a little differently compared to the film it’s based on—a contrast to the 1995 version—and some aspects are enjoyable, like the gore, but overall it isn't something I would choose to watch again. It doesn’t have the same tight pacing or entertainment value as Joe Dante’s movie, and the visual effects aren’t particularly believable either. Seeing the 3D sequences now is amusing (in a regular 2D format, of course). I never cared for that technology, so it's good that it didn't last—it felt like just a flashy trick. Regarding those effects, the way the piranhas are used and how they look doesn’t quite work. I mentioned this before in my review of the 1978 film’s sequel, but: simplicity is often best. The actors are acceptable. Elisabeth Shue is definitely the strongest performer; her character is genuinely interesting, showing agency and competence—a refreshing change from many female characters who seem to be present only for their appearance. Steven R. McQueen also does a good job. It was intriguing to see Kelly Brook involved, someone I know from other projects; it was a clever casting choice, really. Aside from her, Jessica Szohr is fine, but Jerry O'Connell isn’t great. Adam Scott, Ving Rhames and Christopher Lloyd are also in the cast, as is Richard Dreyfuss. It’s preferable to the other sequels made after the original film, and it wasn't entirely terrible, so I suppose it deserves a little credit for that. Still, I wouldn’t suggest watching it.

Source on TMDB