I was so disappointed to learn that Capitol Aquarium closed down a few months ago. Mr. E and I would go down there a few times a year, before he started school full time, and roam the aisles of tanks and gawk at the amazing species (especially that electric eel!).
A little internet search revealed that not too far away is Tropical Aquarium Specialties on Mather Field Road. The store is quite a bit smaller but large enough to hear many "ooooohssss" and "aaahhhhhhs" from the children. The store has a few baby eels, a large cat shark and quite a few Nemo and Dori imitators. But what is really impressive are the live coral plants for sale. Really beautiful.
Whenever we pass the store, the children are quick to point it out and ask to go back again.