I hope I can find some help here, I've read and posted a few messages
here and there, so here it goes.....

I have a 125 gallon (yeah, that's all) pond. It's been up a running
for three years now. I added two comets a few weeks ago and a
Butterfly Koi over a week ago. For the past week, all the fish have
seem to be hidding in the corners of the pond or hiding together at
the bottom of the pond. This weekend, I lost the Butterfly fish.
This AM, I found one of the baby fish, about a year old flipped
himself out of the pond and out onto the ground. Luckily, it must
have just happened and I was able to place him back in the pond and I
quickly got him into a bowl.

I checked the all the levels with the following:
Ammonia - 0.0
pH - 6.9
Nitrite - 0.0
Nitrate - 80!

Yup, 80! I did some quick internet searching and came up with a water
change. I changed 50% of the water and filled it back up and
de-chlorinated the water. I also added some aquarium salt. The fish
are doing a little better, but some are still hidding. I again
checked the levels and all were the same except for the Nitrate that
was down to 20.

Any ideas on the problem?
SHould I be more concerned about the water quality?

This is the first major problem that I've had with the pond and I'm
lucky to say that's all.

Any help would be greatly appreciated.

Thanks,
Kris Kauker
kkauker at princeton dot edu