I agree with exploiting the species we already have here, as there are some gems that are yet to appear on the list. And although rays are awesome, David is right about the 0% chance they will be brought in. However, I think alleyways into broadening the range a species similar to what we have here is not unreasonable. For example: we already keep a few species of bichirs here, but there are many more varieties overseas with the same requirements and habitats that are prevented from entering the country. As is the case with dwarf cichlids, larger cichlids, barbs and many tropical fish that are popular overseas enough to become established in the hobby over here too, yet pose no threat to any NZ environment/species.
And no, Im not a member of fnzas yet.