nope
They aren't actually flatworms in the scientfic sense, but that's what the reefing community calls em. They seems to love detrius.
If you are having issues with them there are lots of controls for them. My suggestion is to limit the amount of detrius in the system by increasing your flow and filtration as well as limit feedings. Biological controls include a variety of wrasses like the six line.
Chemical controls would include Salifert's Flat worm exit.
Flat worm exit is an excellent product and I wouldn't hesitate to use it. just make sure you siphon out as many flatworms as possible first.
Mike