First, identify the species you want and identify your states laws, if there are any, regarding sturgeon. Keeping Sturgeon is illegal in some states. Likewise, finding Sturgeon for your aquarium is only possible if you can convince some hatcheries to sell some fish.
As for species, Sterlets, Shovelnose Sturgeons, and Shortnose Sturgeons (Assuming any hatcheries are even willing to sell some of their fish) would be your best bets. Coldwater fish (Unless your aeration is excellent, only then can you be allowed to keep them at slightly warmer temperatures), so try identifying some other fish. Trout, Perch, some Suckers, and Bass could work. Heck, try making a biotope based on a fast-flowing stream for this tank. Would be a nice project.