Rinse fish thoroughly in cold water; pat dry. Sprinkle each fish with 1/2 teaspoon salt. Place seasoned fish in a covered dish; chill overnight.
Combine eggs and milk; mix well. Dip seasoned fish in egg mixture; coat with cornmeal. Fry in deep hot oil (375°) until golden brown. Drain well on paper towels.
Arrange lettuce on bottom half of each roll; top with fish and tartar sauce. Cover with remaining roll half. Catsup may be added, if desired.