I found a list of illinois places and here is what I found on a few near me.
http://fins.actwin.com/dir/stores.php?c=1&r=27
Strandell's Equine and Pet Center, 2025 E. Algonquin Rd, Algonquin, Illinois, 60102, phone 847-658-8866
They are only freshwater now. They did have some cool freshwater...