Don't know. It depends on which species they are and what they were bed in (if captive bred).
See if the shop knows which supplier they came from (Aquarium Industries or Bay Fish are 2 big suppliers in Aust, or somewhere else), and see if they can contact the supplier to find out. If they won't do that, contact the supplier yourself and ask them.
AI (Aquarium Industries)
Each week, Aquarium Industries posts a list of the stock that we currently have available for order on our website as a downloadable excel file.
www.aquariumindustries.com.au
Bay Fish
Listing of LIVE FISH products
www.premierpet.com.au