A dead bighead carp was found floating on the Fox River near Montgomery on Saturday. Upon farther review, as the commenter noted, and several professionals agreed, it is a grass carp.
Don Rego, president of the Illinois Smallmouth Alliance, reported the find. He said the IDNR will be notified within a day of the 36-inch carp.
The Dayton Dam had been considered a block to the advance of Asian carp--bigheads and silvers--on the Fox from the Illinois River. Many are stacked up below the Dayton Dam.
A floating dead carp doesn't necessarily signify anything. It could be a rogue fish or a bad joke by an angler who snagged it at Dayton or Starved Rock and took it upstream.
Or as it apparently turned out, be a grass carp.
The pictured fish is a Grass Carp.
An invasive species, to be sure, but also widely stocked in sterile form for weed control.
Pretty good chance that this fish is a stocked triploid (sterile) fish that was transported into the Fox by high water.