Ahhhh, the pond. It is no more. After screwing around with it for several months I decided to count my losses and give up on the pond. Soon it will be filled with dirt and converted into a strawberry garden. Of the 17 fish that occupied it, only 2 remain. It was sad watching them die off one by one, but there was not much I could do about it. I tried to maintain that tank as long as I could, and it was just not possible.
The tank has recently been renovated though. New substrate, new filter, new home upstairs in our front room. We also added a ryukin, two shubunkins, and a pleco. They seem to be very happy in their new home.