John,

It is true that zinc can be toxic, but this usually only occurs if you have
very acid water. Many people in Oklahoma have Goldfish in their galvanized
horse troughs that they breed and multiple year after year to the point
where they are used for bait or thrown out. If your water has a neutral or
high pH there is never a problem with it hurting fish.

Now if you were trying to raise Discus in galvanized tanks you probably
would have a problem.

Tom L.L.
----------------------------------------"John Hines"
wrote in message ...
T wrote:

I'm adding an additional filter to my pond. I have a 3 foot gap between
it
and the pond and am contemplating various ways of spanning the distance.
A
rubber lined rock course might be an option. I really don't like the
thought
of PVC pipe. I was thinking about making a trough using corrugated
galvanized metal - that stuff that's so popular on the roofs of barns and
tool sheds. Does anyone know if GALVANIZED metal is fish safe?

It isn't. It is coated in zinc, which is toxic.

Try schedule 80 (dark gray) PVC instead of 40 (white) or DWC which is
green. Cut a real large diameter in half.

Otherwise, go see if you can find some clay tiles, like they use for
roofs, but you invert them so water runs in a stream.