Zoanthid eating flatworms?

[vahegan]

Hi!
My tutty-frutty frag were not opening in the past 10 days and the rest zoanthids too were partially closed, so I suspected I might have a parasite. I took them to a Bayer bath, and there were many small reddish-brown critters crawling out of them. They are about 0.1-0.15" long, have elongated bodies and looked to me like flatworms.
I took them under a microscope:

https://youtu.be/n0H7C4ihNdg

https://youtu.be/LDjaWIgFl3M

What are these? Shall I treat the whole tank with flat worm exit now?

 

[650-IS350]

https://www.thesprucepets.com/coral-eating-flatworms-in-reef-tanks-2924016

https://www.reef 2 reef.com/ams/flatworms-the-good-the-bad-and-the-pretty-terrifying-part-1.530/

My suggestion go to the invert forum and check with Leslie they can help ID it.
http://www.reefcentral.com/forums/forumdisplay.php?f=427

I don't know if that's the correct invert forum since RC looks different to me now since I left long ago.