Les,

There are all kinds of bacteria in the pond. There are ones we call good,
because they perform the nitrification processes. There are other good ones
that we put into the pond like KoiZyme (previously Lymnozime), and then
there are the ones that we put into the pond to break up the solids. If
there is enough solids to support the anaerobic bacteria, then they are bad
because they generate hydrogen sulfide which is highly toxic to the fish.
And then there are the disease bacteria, and they are always present, it
just takes some form of stress, such as parasites, scrapes, bad water, power
outage, etc. for the fish to allow them to start to grow. They are all
there, just not always actively doing their thing.
--
RichToyBox
http://www.geocities.com/richtoybox/pondintro.html


"Carola / Les" wrote in message
. ..
We are all familiar with the 'good' bacteria that we try to cultivate in
filters and gravel etc. but where do the 'bad' bacteria lurk ?
How do we distinguish between 'good' and 'bad'?
Are they in the dead algae that is killed off by the uv light which then
appears to accumulate on the rocks and bottom ?
Is that the black slime that appears on the rocks?
How do we get rid of the 'bad' boys ?
Do we need to?
Les.