Georgia, you are right about "carp fishers" keeping their recipe a secret. As a kid my grandfather liked to catch carp.

Secret recipe that drives carps wild is frozen brine shrimp mixed into a very dough like bait. I had a saltwater aquarium at the time and he "stole" my shrimp for his recipe. He caught easily over a hundred pounds of carp in one day.

The carp was so bad even the cats wouldn't eat it. I believe he used most of it for fertilizer after that.