Feast of the Seven Fishes

The tradition stems from the Roman Catholic observance of abstaining from eating meat on the eve of a feast day.

[1] As no meat or animal fat could be used on such days, observant Catholics would instead eat fish (typically fried in oil).

Nick Vadala, writing for The Philadelphia Inquirer, found the newspaper's oldest reference to the feast in a 1983 article.

Fried smelts, calamari, and other types of seafood have been incorporated into the Christmas Eve dinner over the years.

[1][2] The meal's components may include some combination of anchovies, whiting, lobster, sardines, baccalà (dried salt cod), smelts, eels, squid, octopus, shrimp, mussels and clams.