Water-quality experts said Friday they don't know what killed more than 2,000 fish in Lake Wylie.
The fish kill was in a narrow, 21/2-mile-long section of the lake south of N.C. 27 and north of Wilkinson Boulevard, the Mecklenburg County water-quality office said.
Dead fish were found on both the Mecklenburg and Gaston County sides of the lake.
Water quality is normal, samples show. More fish are not dying, and live fish have been seen in the area of the kill.
Results from more water sampling are expected Friday.
Because the cause of the kill is not known, swimmers, boaters and fishermen should use discretion in that area, Charlotte-Mecklenburg Storm Water Services said in a news release.
The agency and the N.C. Division of Water Quality are investigating the kill.