Jonah's fish or Jonah's Aquarium sells them. I have access to them somewhat on my own and can ship them live to you, but I don't know about thousands. I am in the same predicament about wanting some of each of the 3 Esox Genus of Pickerel species Esox niger (Chain), Esox vermiculatus and Esox vermiculatus americanus (Redfin and Grass Pickerel) for a niche type of species only breeding pond with tons of minnow and shiners as a forage base for a readily available supply for the predatory type aquarium fish keeping trade.
One single 4-5" Chain pickerel sold for almost $200 dollars (& after shipping was added in the total, it was well over that price!!!)earlier this year after a couple of folks got into a small bidding war on who really wanted it the most.
I'm going to try to make a few Blue Catfish, Flathead Catfish, Bowfin, and some of the other predatory type oddball hard to find fingerlings available this way also on my 20 acre North Georgia Farm where I live also.