The girl had been on a family holiday with her grandmother and other children when she fell into the water in Rio Maicuru in Monte Alegre.
Her grandmother told Brazilian newspaper Ariquemes Agora: "I tried to hold onto her, but with all the other children around she slipped out of my grasp.
"I couldn't see her any more when we got to the bank."
The other children were, thankfully, saved by the grandmother.
However the little girl was not reached in time, and a pool of blood and a shoal of piranha fish were soon spotted around her.
![Piranha attacks resulting in deaths are occurring in the Amazon basin; some Brazilian rivers have warning signs about the lethal fish [stock image].](https://images.bauerhosting.com/legacy/lifestyle-legacy/15/b68bb/bf2e4/238a5/f020f/686be/a3bc2/AYHY32_363x646.jpg?auto=format&w=1440&q=80)
By the time she was pulled from the water, the little girl had been partly devoured, with all the skin on her lower body stripped away by the flesh-eating fish.
Shocking pictures of her body, which we have deemed too shocking to include, showed her legs as nothing more than exposed bones below her hips.
Police are investigating the incident, but have said it was a tragic accident that was unlikely to result in any charges.