Ours surprisingly hasn't touched any of the small featherdusters. I figured those would be the first to go, but nope! And yes, they love to wind through the rocks and hover over the sifters catching anything that floats up.
Like SushiGirl's mine doesn't even look at the many small featherdusters in my tank. I wish he did because the dusters were getting out of control so I have to manually remove them.