Wow, you just brought back a memory. I remember going to Ed's in Queens and then when we moved there was also one in Farmingdale. Ed's had a nice design I think it was cave-like and I agree it was a special place to go for fish.
I remember going to the one in Lynbrook, and seeing small plastic containers of killifish eggs on the counter (don't remember the species). After all these years, that's what really sticks out in my mind, aside from the wide variety of fish.
If you were lucky enough, you got invited to see the fish in holding in the basement, something I never got to do while the store was open. Many years ago, though, the landlord of the building contacted the NY Aquarium, asking if we wanted the tanks in the basement, and whatever equipment was there. Of course, we went and started picking through things. Rows upon rows of 2' x 2' tanks, plus some standard sized tanks, lots of fiberglass tubs, and lots of foods, medications, and misc. stuff. I think all the tanks are gone now. Some cracked, some leaked. I wish I had taken some of them home with me. The tubs eventually delaminated and had to be disposed of. We left a lot there, which were lost when the building was demolished to make way for a swimming pool store. Long Island used to have lots of really neat stores and, to me, today's shops pale by comparison. Or perhaps it's just the rose colored glasses my memory wears when thinking of these things. Nah!