Oh hey I was meaning to tell you, I just found one the other day. It is a truly amazing store! If I remember correctly it was called Advanced Aquarium Systems. It is an amazing store, it is really big and if I remember correctly, they have quite an extensive collection of freshwater fish. Their saltwater, on the other hand, is small and limited to one room, but it has alot of tanks! The person that I met there was really friendly. I even asked for a job application! Wish me luck on that! It has always been my dream to work in a fish store! I hope this helps you though, and sorry mods about the double post!
EDIT**
I forgot to mention, there is a lot of construction on the way down to that store, I was scared driving over there cause it was so confusing! But on my way back, I had no troubles at all! If you know the Green Bay area, then I could help you out! What I did was, I went onto Lime Kiln Road, drive past the Copps and Target mini-strip mall thing, keep driving down Lime Kiln and you should pass Packerland Meat Packing Co., Once again, keep on driving. You'll end up at an intersection of East Mason Street and Lime Kiln, once again stay on Lime Kiln. Shortly after passing East Mason, you make a left at the next intersection on Main Street. Stay on Main Street for quite a while. There is alot of construction in that area so I would just keep my eyes peeled if I were you. Keep driving on Main Street and you'll go across the bridge. After the bridge you should come up to the intersection of Main and Broadway. Make a left onto Broadway and it is right there on your right. There is no parking lot, so you'll have to park on the side of the road, at least I didn't see a parking lot. I really hope this helps you!