Periodically, the filter becomes partially blocked and has to be cleaned so that the pump isn't overburdened. It's not the most pleasant task, but it was Saturday afternoon's. When I was done, I decided that there was too much string algee as well, so out came the rake and we created a nice pile of wet pond sludge on the bridge.
As I went to pick it up so that it could be hauled away in the garden cart, I realized that there were living animals among the strands. They were polywogs, lots of them. We knew the fish had bred, there's been quite a few extra mouths for dinner there, but I now know the frogs have managed also. And the baby polywogs hide in the vegatation so that they don't become meals themselves.
Immediately, the mass went into a large tub, with water over it.
And then, I spent most of an hour carefully pulling strands of pond sludge apart by hand and managed to return about three dozen live ones back into the pond.
Not exactly how I planned the day, but on balance, and after it was done, I'm happy about it.