Sounds like those fish were spawning, and when they're doing that the only thing on their mind is the birds and the bees. I have caught one spawning carp ever, and I think it was more a case of my fly being right in the path of his open mouth- a total fluke. Come back in a couple weeks and watch the fish. Pay attention to where they're feeding, what they're feeding on, and go from there. Carp can be very, very picky, so you have to let them tell you what they want. Be observant, and be smart. If you're interested, there are a number of carp threads in the archives of Warmwater Forum. I suggest you read some of them.