BLT Fish, the new eatery from chef Laurent Tourondel, has only been open for two weeks, but it’s already hot. On the frigid night I popped in for dinner last week, the wait for tables was two hours, which didn’t seem to bother anyone at the bar, where the crowd just kept growing. Such is the good fortune of a restaurant with a successful sibling, in this case BLT Steak uptown, which opened last year with great acclaim (the “BLT” in both restaurant names stands for Bistro Laurent Tournondel – not the sandwich). If the food I tasted last week was any indicator of BLT Fish’s potential, it’s off to a spectacular start.

Restaurateur Jimmy Haber (also of BLT Steak, Pazo, and Restaurant AZ) has opened BLT Fish in his former Restaurant AZ space, a three-story gem of a building that once housed Flatiron hotspot Flowers. On the first floor is the newly opened first “deck” of the restaurant, a buttermilk-colored, New England style seafood shack that looks like it blew in from New England during last week’s blizzard (a formal dining room will open upstairs next month).

Designer Michael Bagley’s recreation of a relaxed seafood shack is at first hard to fathom here on West 17th Street, but after your eyes adjust to the wholesome cleanness of the space (which is pretty bright at night),you get the theme, which encompasses aged brick walls, white wainscoting, and black-and-white photographs of seafarers of yore. Behind the busy bar are a series of blackboards listing seasonal raw bar specials, wines by the glass, and homemade pies.

At the center of the room, however, is what any New Englander would surely call the Cadillac of shucker stations, a chrome crowned circular throne surrounded by tiers of crushed ice and some of the most beautiful raw bar delicacies this side of Balthazar. When I saw the young shucker struggling to keep up with the demand I felt pangs of nostalgia for Blue Ribbon’s now-retired shucking machine, Alonzo Almedia, who masterfully cracked open 2,000 bivalves a week in that restaurant’s first decade. Surely the shucker here will get plenty of practice.

While some of the items here are served in “authentic” seafood shack paper-lined red plastic baskets, accompanied by a trio of condiments – Old Bay, hot sauce, and vinegar – the illusion of a fish shack is shattered once you look at the exacting details of Mr. Tourondel’s cookery. Starters include fried calamari, listed on the menu as “spicy & greasy” ($8), though they are hardly the latter and beautifully the former. The Maryland crab cake ($14) is both meaty and moist, and crisped perfectly. “Peel ‘n’ Eat Shrimp” are fabulous and fiery, steamed in a heady Old Bay brew that is literally finger-licking good. Though the fried oysters ($10/half-dozen) are as good as the calamari, it seems like sacrilege to fry them when they’re so delicious freshly shucked.

Speaking of the raw bar, the Seafood Platter ($58/$98) is the way to go if you’re flush with cash and hungry. They’re piled decadently with an assortment of oysters, clams, stone crab claws, king crab claws, jumbo shrimp, Taylor Bay scallops, tiny periwinkles, tender poached octopus, steamed mussels, cracked lobster, a Dungeness crab, and even a few whelks (spiral-shell clameating mollusks) for good measure. Oyster selections, which change daily, are offered by the piece and listed on a separate menu with accompanying descriptions, such as Hama-Hama, from Hood Canal, Wash., with “salty mild flavor with a fruity aftertaste” ($2.30). I’m not sure I tasted the fruit, but it was mouthwatering with its accompanying mignonette.

The midsection of the menu features more sea-shacky fare, such as the exemplary New England clam chowder ($4 cup/$8 bowl) and lobster bisque ($5/$10). Sandwiches include the lobster roll ($22), a perfectly-dressed, overflowing affair that should give fans of the one at Pearl Oyster Bar pause. The signature BLT Tuna Sandwich ($18) is stunning, the ruby-red barely-seared cubes dressed in tapenade, then layered with bacon, slices of hard-boiled egg, arugula, and tomatoes. Both are served with crisp shoestring fries and fresh slaw.

Main dishes were described by our waiter as “a selection of line-caught fish available grilled or blackened, accented with a variety of sauces, such as lemon hollandaise, spicy salsa, or homemade tartar sauce.” The halibut I ordered with lemon hollandaise ($23) was simply exquisite: salted and seared with a kiss of butter, then roasted perfectly moist. The fish & chips ($14) were better than any I’ve heretofore tasted. Sides included ridiculous quantities of fantastic “onion strings” ($6) and wonderful fried stuffed jalapenos ($7). I’m not sure where the beautifully blackened corn on the cob came from at this time of year ($6), but it tasted pretty fresh, if slightly dry.

As an ode to the best American diners, pastry chef Nancy Olson offers traditional American pies (all $7) for the finale, including a tangy key lime, a savory-sweet berry bread pudding, and a velvety chocolate cake. For an extra two bucks they come a la mode, with chocolate, vanilla, or strawberry ice cream – totally worth it.

BLT wine director Fred Dexheimer, an award-winning sommelier, offers 20 wine selections by the glass, many of them esoteric, such as the 2001 Chamboreaux Savenierres ($12) or the 2001 Pellegrini Cabernet Franc ($10), and a signature “short list” featuring Muscadet, Chablis, and other seafood-friendly wines.

In early February, Mr. Tourondel and company plan to open the elegant third-floor dining room of BLT Fish, where his long-awaited signature seafood dishes will finally become available. Mr. Dexheimer assured us that the accompanying wine list for that menu will be stellar. I have no doubt that it will be, too.

BLT Fish, 21 W. 17th St., 212-691-8888.