There are many species of piranha, somewhere between 30 and 60, but the true number is still unknown. The largest and most notorious species, the red-bellied piranha, can grow to up to 20 inches long.

Four people were killed and 20 others have been injured in separate piranha attacks in Paraguay this year, causing concern among locals. On Jan. 2, a 22-year-old man temporarily went missing ...

Story at a glance A red-bellied piranha was found in a Louisiana State University lake. Native to South America, the red-bellied piranha can grow to be a foot long and about 4 pounds.