Depending on the loop your trying to make you could hit Fish Den on 44th and Sheridan as well. Ill be honest, sometimes I go in there and Im like "WOW", other times I go in ther and Im like "WTF"
There is also Liquid Kingdom on 120th and just west of Huron in Northglenn, he has a huge display tank which tends to make the trip worth it alone. Store is set up a bit different than most, no prices, you have to flip through a price book. The guy that runs the shop is pretty cool though, has done quite a few special orders for me.