So I went in to see how I might set up the camera and did a double-take... Did I see something move in there?

I've now spent half an hour staring into a tank that would, to most people, appear completely empty. My dogs think I'm insane.
All I have to say is - wow, those things are really, really small - and they are remarkably powerful swimmers for their size.
So I have a Penquin Mini Biowheel filter on the tank, with filter pad wrapped around the inlet and secured with cable ties. After seeing the size of the fry, I modified that by covering it with pantyhose as well.
My questions at this point are:
- Is the power filter a problem? The fry seem to be able to swim where they want to - I just want to make sure that the filter isn't going to prematurely wear them out.
- Do I really wait a few days before feeding them? They are zipping around like crazy - I don't want to wait too long. I got some liquid fry food tonight just in case.
- Do I do water changes? If so, how do I avoid dumping out the babies with the tank water? Inventive ideas wanted...
Thanks in advance y'all,
Jen