> This is probably a naive and idiotic question but if one were keeping fish
> from the Amazon shouldn't one then be injecting micro organisims from that
> environment and not those from the local pond or river?
For a reference on this, read _Dynamic_Aquaria_ by Adey and Loveland.
One of their algae-scrubber setups was a freshwater "black water" tank
with Altum angels and what not. My recollection is hazy, but I
believe they imported a cubic yard of river muck from Venezula for