> One thing that I haven't seen mentioned amongst all of this discussion
re the dangers of hybridization is the natural selection processes. I
know that rainbowfish congregate in schools (for protection?) and I
wonder what the chances are of a male or female from one species trying
to attract a suitable partner from within the school of another species.
This sounds more like mate selection or sexual selection more
specifically than the all encompasing natural selection. Mate selection
breaks down when your choices are limited. If for instance some
australis were released into the Brisbane River it would probably only
be a handful of fish that may or may not school together. If a lone
australis finds a school of duboulayi then it would probably join in with
them. I also don't think there is a lot of mate selection in most bows.
If a male can't find the same sex to mate with him he will go elsewhere
(reminds me of a good joke Dr Minckley just told me yesterday about 3 men
stuck on an island with a female gorilla....... :-) ). There is no
doubt that amongst some rainbows there is a definate preference for their
own type in mixed aquariums. However, males from different species can
also sneak in and release sperm too possibly and you only need a very
small percentage of hybrid fertilisations to screw things up.
> ANGFA was lucky enough to have a talk by Milton Lewis (James Cook Uni)
at our Townsville convention on the processes of natural selection, and
from the basics that I have managed to retain, I would have thought that
cross breeding would be extremely difficult (not the mechanism but the
attraction of suitable partner).