In article , DavidM
writes
Phyllis and Jim wrote, On 19/05/2007 18:48:
We have never tried a totally fishless pond. I suspect it would have
fewer nutrients than our koi/goldie pond as it would have less
fishwaste.

The excess nutrients come from the fish food that we throw in, it is
packed full of calories that the fish turn in to urea.
Many people have low maintenance gardens ponds with a few fish that are
never fed. There is no pumped filtration or outside intervention. The
population of fish (and plants) is self regulating depending on the
available resources. Fish eat plant matter or invertebrates so if the
pond is in balance, the nutrient level will be just right. Probably wont
be a great pond though, and fish will die if the system is unbalanced.

I have a pond like that and it is very healthy. There is one huge Golden
Orfe in it And I have never fed him once. He lives very well on a diet
of small beasties, tadpoles and plants, and grows each year just eating
what is naturally available to him in the pond. The frogs love it too.
The only maintenance I have to do is cut back the plants twice a year.

Angela.