I have flatworms

From what I've read (from wetweb media)the flatworms will come and go with the copepod population which is their food source. I cant find the link right now I'll have to post it later.
I'm not seeing any on the coral just some of the
LR and where the sand bed meets the glass.
Anyone have more info on these guys?
Should I start the removal process or is the info I found on wetweb accurate?