A few blocks west of A World of Fish is Something Fishy, which is not quite as big, not quite as expensive, and generally has better looking fish. Maybe not as many plants, but all in all, I much prefer Something Fishy.
There's also a huge place out in Forest Lake. I can't remember the name, but it's on the main drag on the west side of the street. Pretty nondescript name and storefront, but the back fish room is insanely huge. It's worth a drive to check it out.