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Grass Carp

Grass Carp

Grass Carp (Ctenopharyngodon idella) in South Dakota are large, herbivorous fish that are considered invasive and a threat to wetland habitats as they destroy cover for native fish, birds, amphibians, and reptiles.

Scientific Name: Ctenopharyngodon idella

Physical Characteristics:
  • Can reach impressive sizes - up to 150cm in length and 90 pounds, though fish between 10-25 pounds are more common.
  • They have a sleek, elongated silver/white/gray body that looks more like a huge minnow than traditional carp, with no barbels around the mouth.

What to know

Habitat Distribution

  • These invasive fish are found in specific South Dakota waters.
  • In South Dakota's prairie lakes, they likely cannot reproduce due to lack of suitable flowing conditions.

Key Locations

  • Currently found in specific South Dakota waters including the James River (extending up to Jamestown, North Dakota), the Big Sioux River south of Sioux Falls, the Vermillion River below East Lake Vermillion, the Missouri River below Gavins Point Dam, and Lake Yankton.
  • Lake Byron in Beadle County also contains some bighead and silver carp.
  • Target them in the James River near Yankton where silver carp are abundant, or in Lake Yankton after flooding events.

Specific Spots

  • Target areas with floating grass or vegetation blown into water by wind.

Grass Carp FAQ

Answers from onWater's species guide.

What flies work for Grass Carp in South Dakota?

Effective fly patterns include size 12-16 black woolly buggers, beadhead hares ear nymphs (#14-18), smokejumper midges (#18-22), CDC caddis (#12-14), cottonseed patterns (#12-16), and parachute hoppers (#12-16). Tie flies in three weights: heavy for deep water, medium for slow sinking, and light for suspension.

When is the best time to fish for Grass Carp in South Dakota?

Spring through early summer offers best action as fish emerge from winter dormancy and feed heavily before spawning. During spawning season (May-July), fish should be left undisturbed.

How do you catch Grass Carp in South Dakota?

Lead the fish by 10-15 feet, then slowly strip the fly in front of their face with small twitches. Never set the hook aggressively - slowly lift the rod to 12 o'clock position and let the fish hook itself.

What do Grass Carp eat?

Primarily herbivorous, feeding on aquatic vegetation including cattails, various macrophytes, and can consume up to 40% of their body weight daily - a 62-pound grass carp can eat almost 2 tons of aquatic vegetation per year.

Where do Grass Carp live in South Dakota?

These invasive fish are found in specific South Dakota waters. In South Dakota's prairie lakes, they likely cannot reproduce due to lack of suitable flowing conditions.

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