'TIS THE SEASON for another Italian tradition, the Feast of Seven Fishes, usually served Christmas Eve and sometimes involving up to 13 - but never 40! - courses. Did we say this was an Italian tradition? Some say Italian-Americans came up with the idea to show folks back in the Old Country how good life was here. However it started, the custom's pretty entrenched around these parts now. Here's how several local restaurants are observing:
* Northern Italian restaurant Le Castagne (1920 Chestnut St., 215-751-9913, lecastagne.com) takes a seasonal turn with its Feast of Seven Fishes, on the menu through Monday for $75.



