Flatworms (bening)

[Thereeferboss]

I saw these guys on my glass a month ago and I didn't worry about, I did a water change today and notice this large one, I asked someone and they told me they are bening flatworms, had anyone dealt with them before should I worry or just let them be or should I take drastic measures in my tank. My tank has no fish in it right now since they are in the qt but I do have around 100 different morphs of Zoas. Would they hurt my Zoas if anyone has any experience in these little guys please let me know.

 

[Reef Fever]

looks like an acoel flatworm...relatively harmless but can rapidly spread and block out light from coral