My pond is full of algae. I have tried algaecides (or whatever it is
called}. In a pond about 12 x 14 feet and maybe 3 feet deep in the center
I have three waterlilies, 3 arrowheads, two bullrushes, two irises and about
20 anacharis plants. Also a few parrot feathers. Have a biological filter
and a skimmer. Also have a huge (about 12 " in diameter) ball of barley
straw. And still I have algae.

Sometimes, you're just gonna have algae. But let's talk about your biofilter
size. Your pond, assuming about a 1.5 foot average depth, is about 2,000 gallons.
Maybe your filter is weak?

Right now I am reluctant to run the waterfall which runs the filter and
skimmer because I have a very few baby fish and don't want to hurt them.

If you're not running the filter, you have a problem. A bio filter
really should be run 24/7. Futher, if a biofilter is stopped, it often
kills all the good bacteria that makes the filter work, requiring a
good week or two to get going again once restarted.

Will appreciate your comments.

Once you have established good biofiltration again, and we, the group,
have determined that your biofilter is big enough for your pond, you
might consider a UV filter. Appropriately sized, this will stop green
water dead in its tracks.

A temporary solution, that you could do right now, would be to toss in
a bunch of calcium bentonite clay, while your system is circulating.
You should be able to find this at any koi supply place. Don't be afraid
to use treble or quadruple what they recommmend. Expect muddy water for
a day or so, nothing wrong, to be expected. Then everything should clear
up, see all the way to the bottom type of stuff.

C//