May be a cultural aspect. A British pub grub staple is "Fish and Chips." In the kind of food-oriented gastropub the parent comment is alluding to, you'd see an explicit reference to the species, possibly even its provenance. E..g "Halibut & Chips", or "Line-caught Atlantic pollack served with hand-cut goose-fat Jersey Royal chips". It's really a 180 from no-nonsense pub menus, which are in themselves a recent innovation. (First pub I went to regularly your choice was a packet of crisps or a pickled onion from a dirty glass jar on the bar.)