[Snip]
Grossed out in New Brunswick,
Carole

No need to be grossed out

Based on your description, it sounds like you have daphnia in your pond.
They're commonly called water fleas. Daphnia are harmless they eat algae and
other small organisms floating in the water. You can read about them here
http://www.petfish.net/daph.htm

Just let them live, your fish will eat them, I suspect that almost all of
our ponds have daphnia, they're a common pond insect, and often introduced
to the pond when you add water plants. If it really bothers you that there
are daphnia in the pond, you can try and keep them under control by using a
brineshrimp net from pet fish store.

A 200 gal pond is too small, I bet if you poked around some of the 1000 gal
ponds or larger, you'd find all the things you learned about in high school
biology, like a few fairy shrimp, some cross-eyed planara, tons of dragonfly
larva, daphnia, various aquatic snails, and all kinds of single celled
creatures. It's how nature keeps the pond in balance.

-S