FOOD WATERDEEP

Waterdeep is a cosmopolitan crossroads, with quite a few wealthy inhabitants, so almost every practical and good-tasting culinary dish or knack or new wrinkle tends to get adopted by someone, and persist somewhere in the city.
Local delicacies tend to have either largely died out over the years as the city has grown and stocks have been depleted (e.g. eel pie, gull pie, and the just-as-revolting-as-it-sounds fish sausage) or to be tavern and lower-class daily staples enjoyed by many, but celebrated by few.
These latter include:
•"melverfew," a dish of diced eels, fleshy dark mushrooms, flounder, and harbor catish, simmered in oxen-and-onion gravy until everything is soft. All bones are then strained out, and stale bread is shredded and then stirred in, with a handful of grapes or gooseberries (or in winter, or whenever no grapes can be had) raisins added and cooked soft. Typically this is very cheap: 1 cp for a large bowl, sometimes 1 cp for a bowl AND a mug of small beer.
•Whelks in butter (the yellow-brown-shelled edible marine snails still plentiful along the shore of the Sea of Swords from about Port Llast down to Baldur's Gate; these are unshelled by shattering their shells with a wooden peg or maul, dropping them in water (the shell fragments rise or float, and can be skimmed off, then steamed or boiled in water or old soap leavings, then drained and served in a dish with melted butter and a garnish of fresh parsley and/or chives). This is a dish children can prepare, and tends to go for 1 to 3 cp a platter, depending on the size of the platter and the hauteur of the establishment.

Tharval-and-dleem (tharval are hand-length or smaller, silver, smelt-like fish much used for bait, or mashed into a paste and eaten on toast as many enjoy real-world sardines or kippers, their bones being so small and soft that they can readily be chewed and eaten without discomfort; dleem is a olive-green, stringy seaweed that grows in starfish-shaped clumps, partly clinging to rocks and partly "adrift" in the passing water; if dleem is boiled long and hard, it looses its tough, chewy consistency AND takes on the flavor of whatever it was boiled with, and so is used to bulk up many soups, stews, and other dishes; if mated with mashed tharval, the result has an incredibly rich, "full" taste and texture, so diners feel even ravenous hunger has been thoroughly sated). This is low-end to shopkeeper-class fare, and a daily staple at 3 cp a dish. Garnished with a few oysters and redubbed "Harbor Favor" or "Harbor Fancy," it goes for 1 sp in middling to higher end establishments, for a generous dish plus handrolls of bread and usually a wedge of sharp cheese to provide a contrasting taste.

Sarrulk Stag (Imbram Sarrulk was a glutton of astonishing obesity who died of a surfeit of boar, suffering a fatal rupture after singlemouthedly devouring no less than five whole spit-roasted boar back in 1312 DR; he is credited with devising this recipe, which took High Forest venison and divers rodents [city rats and mice], oxen, old mules, and whatever other handy cheap meat could be had, marinating them for two days and nights and then roasting them, all in the recipe's long list of herbs and sauces, plus drippings and beer - - and somehow making it all taste like the venison; so only nobles and the very wealthy ever have actual stag in their Sarrulk Stag, but everyone can dine hearty . . . hopefully not quite as heart as Sarrulk did). The time needed for preparation and the popularity have always made this stew pricey, so a bowl, garnished with fresh greens, typically costs 2 sp in a cheap eatery, and climbs up to 8 sp in a haughty club (with most places charging 4 sp or so). Outside the city, cut these prices in half.

Yes, it's reasonable to have raw fish (never served whole, but always filleted/deboned and washed in fresh water that's been "minted" with a few sprigs of fresh mint) available in a decent, respectable "middling" tavern.
By the way, high-end Sword Coast elven fish fare would include:

rare delicacies of the seadeeps (giant spearfish, rock reef crab) served raw (but of course "gleaned," that is: just the flesh, washed in steaming-hot spring water) but with berry- and sherry- and zzar-based "laving sauces" (we might call them "dipping sauces") on the side.

Bluehulk (giant tuna) poached in blended wines

And lower-end but respectable Sword Coast elven fish fare would include:

oysters steamed in beer but served in a cream sauce (dill, leek, chives, but not onions or garlic, because most elven palates find these two overpoweringly strong - - and in fact they are elven "wayfaring staples" for use with rancid/bad food in emergencies, to entirely cover the taste).

Dlarkult, which is diced small shrimp and crab, simmered in a mixture of melted butter and a light white wine (almost like a real-world risotto)

Wine

Lythton Wine

THO 1/11/12, replying to query about wine in "Elminster's Forgotten Realms"

"A dry white," but that's literally all I have, and must stress that was overheard gossip among merchants.