I`m no expert but we suffered a similar fate,not long after the waterfall
was up & running, this green stuff started to appear,at first we where
impressed at the speed of nature.This however turned out to be "blanket
weed" which quickly got a good hold on the waterfall & around the edges of
the pond,it was also all over some of the oxygenating plants & it took
several treatments (over a period of a few months) of a brand name to make a
dent in it,& eventually get rid of it, well almost.The treatments we used
had no detrimental effects on the fish (goldfish,shubumkins & other smallish
breeds) which are still growing,so I take it they must be quite healthy.As I
say I`m expert but that`s what we did & it proved to be a success.Hope this
helps....max
"Bob Knight" wrote in message
...
This is our first year having a pond and it has been a learning
experience.
One problem we may be having is this dark green film on the rocks where
the
waterfall happens. We have 10 goldfish in the pond and they seem to be
doing
fine, but I wonder if this green stuff is normal.

What is happening with this green stuff?

Bob