I don't know about availability of barramundi in the USA or the laws regarding their stocking in farm dams. There is an Australian company exporting fingerlings to the USA for growout in sheds.
Water temperature is critical with barra. Below about 20C (68F) they will not feed and die somewhere around 10 to 15C (50F - 60F)
I could probably find the name of the company that has live barra in the US if you are still interested but don't know if they would sell them live.