Planaria ... Problem?
I've been in the habit of turning my aquarium light on for a few minutes at night (to see my RCS as that is the only time they aren't hiding under a piece of driftwood) and I've started noticing a few small Planaria sliding around on the glass. I'm not sure if they have always been in my tank and I'm just noticing them now, or if this is a recent development. I usually only see between 3 and 6 it a time, and they are really pretty small, like ~1mm long. The smallest ones are white, and the larger ones have more of a greyish pink color.
Should I be trying to exterminate them? Is this a sign of poor tank health? Can they hurt my fish, shrimp or plants?
If they are bad, can anyone recommend a product or maintenance strategy to get rid of them?