A woman in her 20s reportedly lost all of her toenails after allegedly getting a so-called “fish pedicure,” a treatment touted by many as rejuvenating for a person’s feet. The toothless carp fish – which are plant eaters – voraciously feast on dead human skin. The woman’s toenails will likely return, but it will take a long time as nails only grow about one millimeter a month on average, Lipner said.