I wish I was paying more attention when I was growing up in South Bohemia (Czech Republic). Majority of the carp raising ponds or Europe are there, and in Austria. Here is a webpage of the main city, Trebon. Unfortunately, there is no English version, but you get the idea from the pictures. They have a trademarked strain of carp, named after the city. Notice the biggest carp in the world, made up of the residents in the town square, lol.
http://www.trebonsko.cz/kategorie/trebonsky-kapr/Most of what I can tell you from the webpage, and from my youth, has already been said here: The food carp get raised in large ponds with very little vegetation, save for the cattails, and some occasionally hydrila, with no other fish stocked with them. They love to splash between the cattails in the shallow water, when they spawn in the spring. Majority of their food is natural from the ponds, but they are supplementally fed pellets - and if I remember correctly, corn. Like with most fish feeding, you have to be careful how much you feed, because overfeeding can have detrimental effect on your water quality. In Czech Rep. these ponds are hundreds of years old and considered historical objects, so maintenance can get expensive.
Carp get harvested around November (for the Christmas table), at between 3-4 yrs of age. They are kept in clean water until Christmas and then sold live at grocery stores. "Generational" breeder carp are babied in separate ponds under very good conditions and artificially inseminated to increase yield. It seems like the ponds were emptied and harvested every 2-3 yrs. Many people come to watch the occasion, and warm themselves with liquor while they watch. The whole thing is firmly ingrained in the history and traditions of the region.
Carp are very strong fighting fish, but also very smart. I read an article about the biggest carp caught in the UK. It went into some public aquarium, where the fisherman who donated him came to feed him every day. The carp learned to recognize him and ate all kinds of food, but till his death he never again ate the bait that he got caught on. If you think about it, the same happens with other kinds of fish. After a while certain types of lures stop working. Most carp remember where and on what they got caught, but I remember a few that got caught in the same spot on the same bait. Their version of Darwin awards, I guess.
I read somewhere that the meat is comparable to salmon, except with those fine bones. I don't like salmon that much, except smoked, but I love smoked carp, fried carp with lemon juice and mashed potatoes, carp fish soup made from the heads, eggs, etc.
I hope some of this helped.
