They aren't viable. They almost all die shortly after hatching, if they make it out of the egg at all. A very small number have survived, but they're anomalies, not 'magically strengthened' as some people desperately hoped/believed. They originated in Europe (well, obviously Australia, but the first albinoes were produced in Europe, and any from that line anywhere else came from it).
In reality, it's a myth that deleterious single gene mutations can be strengthened through outcrossing. This myth is partly propagated by people who honestly believe it, and partly by people who do know better but are lying through their teeth in order to misrepresent their animals.
With some luck, an unrelated mutation will become established in the hobby. It'll almost inevitably happen sooner or later, but it might not be soon. That line was never viable and never will be, and albinos produced from it come from hets.
Incidentally, multiple non viable morphs exist which people who believe the 'outcross strengthening' myth painfully work with in the desperate hope of 'curing the problem', never with success. Sometimes such projects even get sold for a lot of money. I've considered contacting some of the people working with them or who were in the process of buying them (being ripped off, sometimes for huge dollars), but 'shoot the messenger' is too common a game, so I just tend to let them be.
