Bonebuster took the words out of my mouth. I wouldn't suggest eating any wild bottom feeders in much of the country.
Depending on the waterway, you're likely eating very polluted fish.
Even some perfectly safe looking, beautiful trout streams, like the Pere Marquette River, which is even a National Scenic River, aren't safe for eating much. For kids, don't eat more than one trout a month, even if only 8".
The Michigan DNR even states so on carp...
4. Don't eat fatty fish like carp and catfish from polluted waters. Most chemicals (except for mercury) collect in the fat. Buy catfish from your grocery store instead.
Here's the Michigan fish consumption guide. Scroll down a bit to page 7 and the big graphs. Notice the difference between what men and women and children can eat. To me, feeding a wild carp to my kids from the typical Michigan waters that would hold carp would be like handing them a pack of cigarettes and a lighter and telling them to smoke up.
Now maybe west of any major industry, like west of the Mississippi may be OK or in the deep south, but if east of the Mississippi or the upper Midwest and east, all that stuff that went airborne from the 1890's thru 1970's drifted east and settled in the lakes and rivers. The more fatty the fish, the more that stuff stays in the fish.
That's why Great Lakes salmon and lake trout are also something you should limit eating.
http://www.michigan.gov/documents/FishAdvisory03_67354_7.pdf