In Spain, Fideos is a general word for any kind of noodles or pasta, whether made with or without egg in the dough. (Yes, the word pasta is also used interchangeably in Spain.) It can be any kind of shape, from teeny stars to macaroni to spaghetti. “Fideos Corbata” are shaped similar to Italian farfalle; “Fideos al Huevo” is pasta with egg in the dough; “Fideos Nido” are long noodles, thick or thin, dried curled up in the shape of a nest.
Often referred to as a “Catalonian specialty”, Fideos (aka pasta) is in fact cooked throughout Spain, as you would expect in this day and age, though it is true that the habit of eating pasta goes back further in Catalonia. In Catalonian cooking, the pasta is often cooked right in its sauce, as opposed to being boiled separately.
In Mexico, Fideos refers to just very thin, long pasta, similar to Angels’ Hair pasta, dried rolled up in a nest. Sometimes it’s fried up first briefly in fat before being added to a dish.