Manhattan aquariums in LIC is sometimes open to the public via flash open-houses and if you call them they sometimes will let you visit by appointment. Unpredictable whether anyone will answer the phone or respond to your VM or email. If you're looking for that LFS feel though NYRA is the way to go in Queens. Never been to Kissena or KHC as I always thought they were primarily freshwater but I guess I should check them out. There are also some good stores out on LI if you have a car and are willing to travel a little further out. The Aquarium Shop, Reef Shark and Tropical Island aquatic come to mind. Pieces of the Ocean in Staten Island is always worth a visit. There's a place called the Reef Shoppe in the Bronx that is supposed to be well priced but it's unpredictable when they're open and they have virtually no online presence. I've showed up to the store twice during advertised open hours only to find I drove an hour to find a closed store. In Brooklyn you have Mos Reef and Exotic Reef Aquatic which are solid. NYaquatic in Yonkers will have the best deal on fish and have coral as well. You can go to the store or buy online and have uber courier deliver to your home.