Expert: Brigitte - 6/24/2009

Question
I put 10 small goldfish in my pond in April.  They were doing well - several grew to about 3". However, they have been dying for the past month and I now have 1 left.  They look fine - no sign of disease. Before they die, they hang out at the surface of the pond for a day or 2 and then the next morning they're floating. I have been checking the PH and it was low so over the past 2 weeks I have been raising it slowly with Microbe Lift. There is a waterfall and 2 ponds (one empties into the lower pond where the fish are) and I have been cleaning the pump filter so that there is a strong flow of water into the lower pond. I really don't know what else to do or what is going on in the pond. Any suggestions?

Answer
Hello Karen!
The symptoms sound pretty classic for nitrite and/or ammonia poisoning. You may be cleaning the filter too good and destroying the beneficial bacteria colony.
Ammonia and Nitrite levels must be at absolute zero. If they are anything other than that the fish cannot be fed and 1/3 water changes done daily until they return to zero (do not forget to de-chlorinate the new water).