Carp is actually the animal of choice for a Czech traditional Christmas dinner. The traditional way of doing things is to buy the carp live a week or two before Christmas, take it home, put it in the bath, and then kill and chop it up the night before. I think it is an attempt to clean the fish a bit, but I am not sure.
Outside pretty much every supermarket at the moment are pools of live carp. They can stay alive for up to 40 minutes in a Tesco carrier bag, which is more than enough time to get them home and in to their new clean water. It’s an acquired taste. One that I haven’t acquired yet, even after 20 years.