I used to catch HUGE carp down in Texas. Especially, Lake Limestone. I would take 3 poles. Fish one with a crappie rig (some of the best crappie fishing in the states), one for carp, and one for reeling in catfish or bass to keep myself busy. I never kept the carp (takes some skill to clean, pain in the ass. There was usually someone who wanted them.), but I love fighting those things. They are tough and you need some decent gear for the big ones. Now, I haven't seen any more than a 2-2 1/2ft long here, but those are just along the shore. If you want to get your kid addicted to fishing (or scare the shit out of them) fish for some carp. We always used corn down south.
What's funny, is that there are two little hidden ponds/lakes near my house in Delaware chock full of these things so I decided to pick up some canned corn just yesterday. In the evening, I can stop just about anywhere along river rd north of Delaware and find them all along the bank of the river, too. Bow fishing or spearing would be super simple, too. Just be sure to move real slow. No fun in that, though, unless you're utilizing them.