Hi, I'm a new member and I have a big prob;em with my koi pond. I live in NJ
and have had 2 Koi ponds for 10 years. Recently I have had a major problem with
my big pond. Its a 5000 gallon pond. The fish in the pond are 5-8 years old.
Most are 18-24 inches long and very healthy. A third of the fish are actually
babies that grew up. The pond has maintained 23 large fish for many years. I
have had no deaths until recently. In June 2009 I bought a used Bead Filter that
was used by a pond store indoors. I always had ultraviolet lights - but I
decided to add a new unit with 6 bulbs. I use a skimmer as well. I dont over
feed them - once or twice a day - as much as they can eat in 2-3 minutes.

The water never looked better.

In the last week I have lost 10 of my 23 Koi. I started treating my pond with
Melafix 2 days ago. Three fish died since the treatment started but I believe
they were already weakened.

I bought a testing kit and before I added any Melafix I got the following
results:

1) pH - 8.0
2) Amonia - 0
3) Nitrite - 0
4) Salt .50
5) Phosphate - . 50
6) KH - 135 ppm

I added a little more salt then started treating with Melafix. Today I added a
broad spectrum antibiotic that turned the water blue.

Do you think my fish could have caught something from the used bead filter?

My little pond is doing great and its next to the infected pond. I have made
sure not to use any nets or equipment that is used in the big pond.

I am going to have a necropsy done on the next fish that dies.

Any advice you can give me would be highly appreciated.

Thank you,

Bob Cutrupi