Niagara police say the 17-year-old boy was arrested on Tuesday but released few details on his apprehension due to an ongoing investigation.
One teen died on scene and two others were sent to out-of-town hospitals following the shots fired incident near the Great Canadian Midway around midnight on April 8.
Detectives say all the boys they believe were involved in the shooting were under the age of 18.
Investigators have been seeking the whereabouts of a blue Ford F-150 Super Crew four-door pickup seen fleeing the area after the shooting.
The truck was headed west on Lundy’s Lane toward the Montrose Road and Highway 420 area.