They appear to be hit-or-miss in IA but that would be your best bet as long as it is legal to catch and take home. I don't think I've ever seen any native sellers carrying them.
i castnetted this pumpkinseed that was amazing with color and i gave it to my cuz to hold it to get the bucket and she dropped it bak in the water!!!!!!!!! and that was wen i dident kno how to castnet till my friend showed me so it was the only fish in 3 days!!!!!