Sort of looks like "iron bacteria". You will see them in streams where anoxic water seeps in. Non-toxic as far as I know but can clog things up. Good source of protein :)
We use a 5micron filter to keep stuff like that out of our trailer. And as long as the water source is chlorinated sufficiently we're usually ok with it.
The worst water we've encountered was in a small Minnesota State campground, very cloudy, but the guy-in-charge insisted it was drinkable. Couldn't taste any chlorine though. We threw out the filter afterwards.
