George,
Thanks for your thoughts.
I tested the water and forgot to give the findings in my original posting.
Sorry--
PH -7.4-7.6
Ammon-- less than 1 PPM.
Nitrite-- .25
water temp- 80 degrees

All of the above seem to be descent. PH is a little high, but seem to be
acceptable. What do you think?

Chemical Poisoning-- it would have to be airborne because I don't do any
fertilizing or pesticides in my back yard. And there is no risk of runoff
into the pond. I thought of that when I did the water change. I was
hopeful that doing the water change would have diluted any poisoning taking
place. It didn't seem to work as I lost 3 fish today.

I am going to increase aeration to try to deal with oxygen.

Any ideas about bacterial infections and how to treat them? There isn't any
outward signs on the fish.

Any help would be appreciated.
Ray



"George" wrote in message
news

"Go Fig" wrote in message
...
In article ,
ray hucek wrote:

I am in need of some advice and hope you could help.

I am having a fish die-off. They are goldfish and the pond is about 6
years
old. I have never had anything like this happen before. There aren't
any
appearant signs of infection on the fish. The only symptoms that I see
are
listlessness at the end of their life. They lose their appetite.

There haven't been any plant or fish additions to the pond. The only
connection that I have seen is this-toads come to mate in my pond as in
previous years. This year, I found a dead toad floating in my pond,
which I
took out. That was about 3-4 weeks ago. Later, all of the tadpoles
died
off. There currently are more and they seem to be doing all right. In
the
past week, I have had 1-3 fish die every day. Is it possible that the
toad
carried a virus that infected the fish?

I have done a water change this past weekend of about 30%. I medicated
it
twice with a combination of formalin and malachite green. The pond is
about
3,000 gallons and has an external filtering system.

I am at a loss. None of the diseases that I have seen described match
this.

I am hoping someone will have some suggestions.

Did you have a short spring season? Perhaps the parasites, with a
quick rise in water temp, got ahead of the fishes natural immune
systems.

I would use something quite a bit stronger than formalin... perhaps
copper or dylox and increase aeration.

Malachite green is a copper compound. Before I starting adding chemicals
to the
water, it would be wise to determine the water quality first. But my gut
reaction says it could be an imbalance in water quality parameters,
specifically
Ph, ammonia, low dissolved oxygen, some kind of chemical poisoning, or a
bacterial infection.