The only one that stands out in my mind as ever being good was World Wide Aquarium. I don't know if it still exists and it's not so fabulous last I checked :-(.
The only other place I can recommend is ponds and gardens of Limkiln - but that's koi and outdoor stuff.
There used to be a store in Bear, DE (Baltimore side Wilmington) called the Fish Bowl. I never made it up there but they came down to ACA in DC. I met and talked to an employee who seemed nice and knowledgeable.
I sometimes used to make deliveries to this place http://www.wetpetreptilecenter.com/ when I was on my way to Philly - but I don't think that would be on your way there.
I remember thinking they had nice stock and a clean, friendly store.