hi, i have been breeding these little guys for a while. I got my original stock from "the auction site" but alot of pet stores also have them from time to time. I have even sold some back to the pet stores in exchange for other items.
The following website really helped me when starting out breeding.
http://www.shrimp.webplatez.com
Also remember that when adding salt to get them to breed use aquriam salt and not iodised table salt!