There are many ways to ensure your meal is fresh. You can grow or raise it yourself. You can buy it directly from the farm. Or you can take it home and let it swim in your bathtub.
The latter method is a tradition surrounding Christmas Eve carp in Slovakia, Poland, and Czechia. A symbol of good luck and classic meat-free meal for Christians, common carp makes a popular holiday dish in Central Europe. Keeping one’s fish in the bathtub for several days likely began as a pre-refrigeration storage technique. Today, some swear the tub time helps cleanse the bottom-feeding carp of any mud in its digestive tract (though NPR points out that actually achieving this would take much longer).
When Christmas Eve arrives, it’s time for the family to kill their temporary pet. After cleaning and soaking the carp in milk, cooks typically bread and fry it or make a fishy aspic. On Slovakian and Czech tables, it’s often accompanied by the likes of cabbage soup (or fish soup in Czechia) and potato salad. In Poland, the dish is one of 12 in a Christmas Eve feast known as the Wigilia supper. The carp’s role even extends beyond the dinner plate: In all three cultures, it’s common for family members to keep the fish’s scales in their wallets for good luck.
The holiday hack of keeping a carp in the tub actually spans religions. To make gefilte fish for Passover and Rosh Hashanah, some Jewish families once used the same technique. Although it’s largely faded from use in the Jewish community, the practice was memorialized in a 1972 children’s book, The Carp in the Bathtub, which tells of two siblings’ attempts to save their fish from the Seder table in New York. While their rescue mission fails, there are quite a few true stories of holiday carp miracles, with families taking a shine to their bathtub pet and setting it free instead of adding it to the menu.