Gerber's gets them quite often. But they can't or won't tell me where they are harvested from. I've had two that appear to each healthy and were eating, then a couple of months later get a fin or scale disease and die within a day of the problem appearing.
I have been talking to Rich at Coral Ranch about getting a shipment of them from Austrailia. He says he's been watching, but they just haven't been available.