What Fish Are in Illinois Rivers?

Healthy rivers and streams abound with life. Here's a look at five fish living in waterways in northeastern Illinois.

Our local rivers and streams are home to many kinds of fish. In fact, the fish and macroinvertebrates—a group that includes aquatic insects, snails, and mussels—are a valuable indicator of a river’s overall health. A diversity of fish and macroinvertebrate species indicates clean water and high-quality habitat in the river.

Here are five fish you can find in our local rivers and streams:

5 Fish in Northeastern Illinois Waterways

1. Golden Shiner (Notemigonus crysoleucas)

  • Appearance: 4 inches long with gold sides, olive back, and silver belly
  • Habitat: Quiet and weedy areas of rivers
  • Behavior: Lives in shoals (large groups) and shares breeding ground with other fish species
  • Interesting fact: Skin cells of the Golden Shiner contain a substance called shreckstoff. If a golden shiner’s skin is broken by a predatory attack, the substance is released. Other shiners can then detect the substance in the water and avoid the predator.
Photo © Jeff Whitlock

2. Johnny Darter (Etheostoma nigrum)

  • Appearance: Up to 3 inches long, narrow with tan sides, black markings, and translucent fins
  • Habitat: Clear, slow-moving water with sandy, rocky bottoms
  • Behavior: Dwells along the river bottom with head facing into current
  • Interesting fact: Up to 1000 Johnny darter eggs are deposited in a nest under a rock and aggressively guarded by the male fish. The males also clean the eggs frequently and eat any that are covered in fungus.

3. Tadpole Madtom (Noturus gyrinus)

  • Appearance: 2-5 inches long, dark brown back with light brown sides and white stomach; also has mildly poisonous fin spines
  • Habitat: Turbid water, muddy bottom, and thick vegetation
  • Behavior: May attach eggs to submerged garbage
  • Interesting fact: The “tadpole” part of the fish’s name comes from its rounded tail fin, similar to a tadpole. “Mad” may refer to its habit of darting in random directions when pursued by a predator. “Tom” is another name for a cat, and a suitable descriptor for this catfish.
Photo © Ohio DNR

4. Shorthead Redhorse (Moxostoma macrolepidotum)

  • Appearance: 10-22 inches long, silvery sides, and bright red-orange fins
  • Habitat: Clear, fast-moving water with sandy bottoms
  • Behavior: Females can lay up to 40,000 eggs in one spawning
  • Interesting fact: Redhorse fish, like other suckers, are extremely sensitive to water pollution. Hormones from oral contraceptives and runoff from agricultural fields often bioaccumulate in these fish, which can lead to harmful health effects for the fish and their predators.
Photo © Maryland Biodiversity Project

5. Longnose Gar (Lepisosteus osseus)

  • Appearance: Up to 6 ft long, slender body, brown or green fading to white on the belly, elongated mouth with a row of sharp teeth, armor-like scales
  • Habitat: Slow streams and backwater pools
  • Behavior: Ambush predators of smaller fish
  • Interesting fact: Longnose gar populations are declining due to a variety of factors including overfishing, habitat loss, and pollution. They are targeted by fishermen as a trophy fish and are rarely eaten.
Photo © UniProt

Local Groups Are Working to Help Fish and Improve Water Quality

The Lower DuPage River Watershed Coalition, Lower Des Plaines Watershed Group, and DuPage River Salt Creek Workgroup are three watershed groups working in our region. They actively monitor local waterways and coordinate projects to improve water quality, habitat, and diversity of aquatic life in rivers and streams. Thanks to their projects, we’re seeing long-absent fish return to parts of the stream where they used to live!

To learn more about the watershed groups visit www.ldpwatersheds.org for the Lower DuPage River Watershed Coalition and Lower Des Plaines Watershed Group, and www.drscw.org for the DuPage River Salt Creek Workgroup.

Two men examine near stream restoration project
Stream restoration projects, such as streambank native plantings and remeandering a channeled waterway, create more habitat for fish.

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