I'm a bit ambivalent about adding ketchup to my Filet-O-Fish.
There are times, indeed bites even, when I crave the addition of ketchup.
Then there are those times when I think it detracts from the very quiddity of the Filet-O-Fish (and in many ways masks and overpowers the sweet-tanginess of the tartar sauce).
Help me out here fellow 'Hounds and FoF Devotees. Where do you fall on the ketchup line?