https://www.thesprucepets.com/coral-...-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/fo...play.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.