If it is aussie barra then you are probably getting the good wild caught saltwater barra, they export the good stuff and we get the rest

Over here if you see wild caught and farmed or imported fillets side by side you can see a big difference, the wild caught salties are a nice pinky white and the farmed or imported freshwater ones are a crappy greyish fillet.
In Australia if you are used to eating freshwater fish like our yellowbelly or cod then you probably wont mind freshwater barra, but saltwater ones are a lot cleaner and nicer to eat.
Don't be too worried about them being frozen they are a fish that does thaw out just as good.

cheers gaff