Let us clear up a distinction first, because it determines whether you leave happy.
A crab house is a specific thing: steamed blue crabs by the dozen or the bushel, Old Bay in a drift across brown paper, a wooden mallet and no expectation that anyone will look presentable afterward. A seafood restaurant is a restaurant that serves seafood. Alexandria has an embarrassment of the second and comparatively little of the first, and the lists that blur the two are how people end up disappointed at a white tablecloth with a crab cake.
Here is the honest map…