I believe that they (red flatworms) came to me in a bag of pods that I got in a trade with someone. They were originally just in my refugium (where I dumped that bag of pods), but eventually made it to the display. I have treated three times with FWE. Each time, I thought I had them beat, but they came back.
I believe that my manderin was eating them, and I tried a 6 line wrasse, too. It's odd, the FWs seem to cover rocks, and patches of sand, but leave corals alone for the most part.
What bothers me most about these things is that I can't trade stuff with anyone. Who wants some Chaeto with fws, or a frag mounted on a nice piece of live rock with a few FWs hiding in the rock?
No, they MUST go. I will get rid of these things if it means breaking down my tank, drying out all the rock, and starting again.
The Nudis are my last chance. I'll try Mark @ Parrots, if he has 'em, they are going to cost almost as much as they would at Critters. At this point, I'm willing to spend what they cost. No doubt, I will need at least five of them.