Purple flatworm, looks like Coraline algae

[Gynmonkey1044]

Can anyone identify these purple flat worms? They look like Coraline algae when they are on the glass, they have the two little horns like red planaria but are definitely purple. Will flat worm exit work on these? In the picture it's the purple on the glass

 

[Reefing102]

Looks like a planaria flatworm. Best to remove or get a predator that eats them. They can multiply quickly

 

[vetteguy53081]

I believe you posted this on another thread. If so, please refrain from cross posting which takes away from others who too are seeking answers. This is an acoel flatworm also called Ghost flatworms. While they are not harmful as red planaria, they in numbers can smother bases of coral and block the needed light for production of zooxanthellae which is their energy source.
Removal can be accomplished by siphoning them with a 3/8" tubing into a nylon stocking and discard
OR
Add a wrasse such as Yellow coris, 6 line, lunare or malanurus OR even a springieri damsel which will eat them

With the number you have, for the next 2 weeks you will have to look for eggs and scrape off as there is likely some and would be future acoels. Eggs are really tiny