> Just on this "local waterways" point - here (Canberra ACT) our water
> temperature at the moment isn't a lot above freezing - it might be 5 or 10
> degrees Celsius at the surface during the day, the point is moot as far as
> tropical fish species are concerned - they'd die in fairly short order
> anyway. So in our local waterways introduction of tropical species, to
> become feral pests, is not an issue.
> I acknowledge that feral aquarium species are a problem in other parts of
> Australia.
So does that mean that you don't think weather loaches are a problem in
your area? How frequently do you think goldfish get released? The main
reason you see it being a problem elsewhere is because there are
relatively few aquarium species that are cold tolerant. However, desert
rainbows would probably do ok. I've had them down to about 3oC
overnight. There are also usually some refuges from this degree of cold
in lakes. Empire gudgeons would probably do fine too. There are a whole
bunch of species that could do ok in Canberra. Don't be complacent.
End of Sermon
Peter Unmack