In the very long Market Watch thread, there was a discussion about where to buy fresh fish in Jackson Heights. As of this summer, there is a great new, albeit temporary, alternative at the JH Greenmarket. A new stand appeared this year - I think it's called American Seafood - and it's really great quality seafood.
I went yesterday and picked up a haddock fillet and sea scallops. Cooked everything last night and it was all very nice. The guys who run the stand were also helpful and pleasant to talk with. Too bad it's not permanent, but good to have while it lasts!