The Shelby County Coroner identified the man as Jonathon D. Oliosi, 29, of Mokena.
The coroner said Oliosi died Sunday afternoon at Shelby Memorial Hospital in Shelbyville. The town is about 35 miles south of Decatur.
According to authorities, Oliosi was fishing with friends near the Lake Shelbyville Dam on the Kaskaskia River when he was struck.
No one else was injured in the incident.
Family members describe Oliosi as a devoted father and Blackhawks fan who enjoyed fishing and playing hockey.
Visitation was scheduled Wednesday.
The Associated Press contributed to this report.