Chopper 6 was over the scene at Sahara Sam's Oasis Water Park in West Berlin, New Jersey.
Officials tell Action News the stabbing happened around 1 p.m.
The victim was taken to Cooper Hospital. It's not clear what led to the violent encounter.
Sahara Sam's released this statement to Action News following the incident:
"A domestic incident occurred near our entrance today. Our staff and security personnel acted promptly to ensure the safety of those involved and all of the guests at the park. The incident is unrelated to operations at the park and is being reviewed by the appropriate authorities."