A school of carnivorous fish attacked a group of swimmers in Argentina injuring them all severing fingers and toes. On Wednesday morning over 1,000 people were trying to escape the 100-degree weather by cooling down in the Parana River in Rosario, Argentina. As the bathers were enjoying their time in the water they began to notice bite marks on their hands and feet. Speaking with the Associated Press Federico Cornier the Director of lifeguards said that the fish responsible for the attacks were palometas, which are a type of piranha with large sharp teeth.

“There were some people that the fish literally had torn bits of flesh from,” a medical official at the scene, Gustavo Centurion said. Officials at the scene said it was the unusually hot weather that brought the fish to surface of the water. Bait left by local fisherman may have also played a part in the attack. Over 20 children were among those swimming in the river on Wednesday. The children were all injured suffering deep bites, to the hands and feet as well as missing digits.

Cornier told reporters from the BBC that this kind of attack “is not normal. It’s normal for there to be an isolated bite or injury, but the magnitude in this case was great…this is an exceptional event.” The piranha is a tropical fish that live in the fresh waters of South America. They can grow between eight and 18-inches in length and are known for viscously attacking any animal that fids itself in their water. The fish are attracted by blood and once one of them draws blood the rest arrive in a feeding frenzy.