If you can handle koi, they seem more likely that goldfish to eat
duckweed. Our koi take care of all the string algae and the duckweed.

Jim

wrote:
I bought a house with a man made pond about 15' in diameter. 60% of
the surface covered with either pond plants or shade from surrounding
trees. I have a waterfall pump circulating water from one side through
a hose to the other side where it spills it back into the pond.
Unfortuneatly, the surface has been growing a green algae and also
thousands of tiny yellow/green seeds or leaves are in the pond. Are
those tiny seeds part of the algae or a product of one of the pond
foliage? I currently don't have any fish in the pond; would adding
fish make that go away? If not, what can I do to keep it relatively
clean?
thanks!!