If you are going cool water, limited gape species stock BNM [bluntnose minnow] and SFS [spotfin shiner]. Apparently BNM are more evasive than FHM, meaning they might establish a population or last longer, and the SFS reach smaller maximum size than GSH which allow adults to serve as forage. Think multilayered forage base for a fishery like this. BNM will spawn like FHM, those tires in shallow water 1-3' depth should be perfect. SFS require cavities in which to spawn - Bill Cody created structure using dowels, milk jug caps as spacers between cds. SFS deposit eggs in between the cds.