Sixty people, including more than 20 children, were left injured in a piranha attack after enjoying a swim on Christmas Day.
A seven-year-old girl who lost part of one finger and a boy who was left with an open fracture in his hand were among those injured.
Other people were left with deep cuts to their ankles, fingers and hands.
Swimmers were enjoying a swim in the Parana River in Argentina when a group of piranhas attacked.
Coastguards called in paramedics so the most seriously injured could be treated. Police temporarily closed off the beach, forcing people out of the water.
The attack was caused by a piranha cousin called the palometa, sources say. The attack is the most serious of its kind in Rosario since 2008 when 40 swimmers were hurt, the Daily Mail reports.
Gustavo Centurion, a medical official, said the fish are “very aggressive.”
Officials said the unusually warm weather is a reason why the fish were attracted to the river’s surface.
The city has been hit by a recent heat wave with scorching temperatures of more than 100 degrees.
Local government spokesman Ricardo Biasatti described the attack as a rare occurrence.
“This sort of event in the area is absolutely sporadic,” he said. “It was the conjunction of two factors, a shoal that passed very briefly through an area full of people.”
Sources: AFP, Daily Mail