Ah man, that's a bummer about Sailfin. They used to be top in my mind...but that was quite some time ago, for sure.
For Bloomington Premium Pet Supply has been around for a bit, and their selection is OK. It doesn't seem like they have anything much above and beyond what Petco, et al carry. Then there was Marine Aquatics in Normal, and then Bloomington. He was an enthusiast as well, so it was generally a pleasant experience. Unfortunately he went out of business. Then there was the Pet Supply Center on Linden in Normal that had a lot of tanks. Some rare fish and lots of plants, too. They have also closed. I think there was a startup in a warehouse type setting east of the airport, too, that closed. Seems like a bad town to keep a fish store going.
I'll definitely check out Natures Select, though. Thanks for the info!
Edit: Oh yeah, I just learned that The Shrimp Farm is here in Bloomington, too! I sent them an email to see if they have a storefront, or if they are just a online/drop ship kind of operation.