Have to say, not a fan of Fishbar at all--thought it was very, very average and quite expensive. I think we have a lot of better options in the area--in fact, for seafood, GNR New England Seafood Co. has really improved the decor inside to be more of a "restaurant" v. just a bare bones fish house--and the food remains terrific.
I'd also second the recommendation for Spanish Square for heavy snacks--I really like the place--if you go, don't miss the giant olives skewered with anchovy and pickled pepper, the jamon iberico toast and the absolutely lovely sparkling rose if it's still on the list--I drank a lot more than I'd planned of it the last time I was there. I'd also suggest stopping through Lincoln Square since you'll be coming from up north--options include Fork, Luella's, Gather and Roots/the 6th (cocktails--great ones!) and, of course, Rainbow and Aroy! Lots and lots of options, that's for sure!
"Knowledge is knowing a tomato is a fruit; wisdom is not putting it in a fruit salad." Miles Kington