The Feast of Seven Fishes is a southern Italian tradition that is catching on again among the descendants of the Italian-American immigrant community. The basic idea is simple: while awaiting the birth of Jesus, we abstain from meat and dairy foods. Naturally for Italians this is an invitation to get creative with fish, so traditionally we prepare a feast featuring seven different seafood dishes and as many vegetarian dishes as you like.
It is also important to note that southern Italy has historically been very poor. It certainly was during the great waves of immigration from there in the early Twentieth Century. Many of the dishes passed down through family tradition reflect this: smelts, sardines, octopus, eel, baccala, and anchovies in pasta all are common foods in the feasts that strive for authenticity.
There's really no point in trying to get too authentic about the seven fishes, since many of the seafoods and other ingredients are not available in New England. A certain amount of substitution is unavoidable, which brings up the idea of following the tradition in spirit more than in substance: if my great-grandfather in Campania were to celebrate Christmas Eve in foodie style, how would he do it? If he immigrated to Plymouth, how then?
The Ligurian/Genoese Cappon Magro, an invention of northern Italy, is certainly an excellent start. It can include shrimp, scallops, lobster, and firm fin-fish such as salmon, swordfish, tuna, and halibut. A big enough Cappon Magro could include all seven fishes!
Suppose you are bringing something to a relative's house to celebrate? That carefully-constructed Cappon might not travel well. A Cold Poached Salmon is easy, tasty, and travels well if you have a good platter and a flat place to set it (the trunk of your car is probably level).
If you are riding with someone or taking public transportation, bringing a long fish platter would be impractical; consider a Lobster Salad in a well-sealed container, and a little bag with some sliced cucumber, chopped parsley, a lemon, some leafy kale or other garnish to make it look nice in whatever serving dish comes available. If you cannot count on a serving dish or appropriate utensil being available, remember to bring that along.
What if you are joining a feast but do not have access to a good fish market? That's where the baccala comes in! Consider the delicate Venetian Baccala Mantecato, but remember to start freshening the fish 24 to 48 hours in advance!
Finally, if you have no idea what to bring or cannot bring a nice fish dish, you can bring a wine to go with it. Italy produces many good wines to enjoy with fish. Some of our favorite readily-available Italian wines for fish feasts include: Principessa Perlante Gavi, Vermentino from Sardinia, and Verdicchio. Falanghina, a sadly-overlooked classic of Sicily and Campania, is harder to find, but worth looking for. The Pescevino in its fish-shaped bottle is not excellent wine but it is cute and serves as a conversation piece of sorts.