The people in the restaurant raved about the carp, and Guy Fieri loved it too. You could probably find the episode on YouTube just search for Diners...etc. and the word carp.
Estuaries are tidewater, open to the ocean on one end, with fresh water entering near the headwaters.
As a result, you get a variety of critters adapted to one, the other, or even both environments (salt and fresh water), but more generally, best suited to the brackish water we fished in.
Those (yellow carp) are beautiful fish, and would be better than starvation, but generally those carp tasted like marsh mud.
I don't doubt what Guy Fieri was eating was good, I enjoy watching his show and have little doubt he likes good, basic, food.