Here is a list of fish species found in the Rock River and Lake Koshkonong, according to a federal report.

Gamefish

Smallmouth bass
Channel catfish
Northern Pike
Sauger
Walleye
Saugeye
Largemouth bass
Muskellunge
Tiger musky
Brown trout
Brook trout

Panfish

Bluegill
Pumpkinseed
Green sunfish
Orange spotted sunfish
Black crappie
White crappie
Rock bass
Yellow bass
Black bullhead
Yellow bullhead
Brown bullhead

Rough fish

Stonecat
Bowfin
Longnose gar
Carp
Sheepshead
White sucker
Golden redhorse
Shorthead redhorse
Bigmouth buffalo

Forage fish

Northern hog sucker
Quillback
Common shiner
Spotfin shiner
Spottail shiner
Golden shiner
Bluntnose minnow
Fathead minnow
Brook silverside
Central stoneroller
Largescale stoneroller
Lake chubsucker
Logperch
Slenderhead darter