I have not been the the Oceans & Sea one so can't speak on that one, but I do go to The Aquarium Shop in RO as well as Atlantis in Clawson quite often. Of those two the Aquarium shop is ther better shop. Atlantis is a very very small shop and only has a very limited assortment of FW fish, no live plants that I know of, and not very much stuff to look at. The Aquarium shop has a better selection by far. But if you're gonna be in this area Jenna then I would say to head to Royal Tropical fish on Woodward just N or 11 mile rd. They have a much larger selection of fish and plants and it is only a couple miles from both the other shops you mentioned.
Be sure to call to see what time they close though because they have a few days a week that they close earlier and a couple they stay open later.
Steve