There are several set lunches with fish. My favorite is the fried flatfish with vegetable sauce on it. Fish are deeply fried so you can eat even bones.  The thick sauce includes carrot, shiitake mushroom, other green vegetables and is well flavored. There is also a piece of fried rice cake in it. A set lunch includes two side dishes (they changes from day to day) rice with boiled and dried baby sardines, miso soup, a small piece of omelet and pickles.
Fried grilled salmon and grilled codfish are also fabulous.

Set lunch
-grilled salmon  1,200JPY
-fried flatfish    1,200JPY
-grilled codfish   1,300JPY

Ichiraku (一楽)
4-6-5  Shinbashi, Minato-ku, Tokyo
5 minutes from Shimbashi Station
Mon-Fri      11:30-13:30