According to Leo Rosten's The Joys of Yiddish, there are references to it as far back as Poland in 1610. They are also quite good with cream cheese and a thick slice of tomato. Those hockey pucks that you find in your grocer's freezer bear little resemblance to a real bagel. A real bagel is soft, warm and spongy inside, lightly crispy outside. A fresh bagel does not need to be toasted, and should not be.
Toasting is a sorry attempt to compensate for a sub-standard bagel.
Enjoy the ease of Shopping for the Jewish Holidays at Katz's. Fish Gefilte fish is a cake or ball of chopped up fish. My brother's girlfriend describes it as Jewish Scrapple, although I suppose that is not very helpful to anybody outside of the Philadelphia area. It is usually made with white-fleshed freshwater fish, such as carp or pike. Some variations on gefilte fish involve stuffing the fish skin with chopped up fish.