Investigators want to know if this has anything to do with last week's train derailment and ethanol explosion.
David Taft found the fish when he went to look at flood damage to his dock. He found 30 dead fish in his yard.
Dead fish have been reported in the Rock River from Ogle to Whiteside Counties.
The Illinois Environmental Protection Agency says it's possible ethanol could be flowing down river, but investigators don't know for sure.
The Department of Natural Resources is also investigating.
