Where does the feast of seven fishes come from

Mark Liberman questions the phrase “feast of seven fishes.”

I was tempted to comment, “It’s called the feast of seven fishes because it’s traditional to serve a dinner with seven courses, all of them fish.” But I resisted.

In comments, Chris asks whether it would it be excessively pedantic to note that only one of the seven is actually a fish.

No, not at all.