Bruce, I used Precision Solution Go to www.aquavisionaquatics.com. If no luck I have some which you are welcome to try. On second thought mine is a billion years old. I pretty sure I got it at All about Fish your favorite. It says treats flat worms in marine systems and reefs.
Got lucky. I got the Onate Wrasse while it was hidden on the top corner of the tank.
It really stressed out by the six line.
Moved it to my 35 gals tank. It's doing ok now.
Found a big Melanurus wrasse at one of the LFS last weekend. This one is about 2.5 times bigger than the 6 line.
So far the 6 line did not bother the Melanurus as it did with the Onate. I guest it did not want to mess up with a much bigger guy.
Let see if the Melanurus will take down the population of flatworm.
I’ve used flatworm exit enough to be confident that it will solve your problem. It should take two treatments two to three days apart. Just make sure to have a water change ready. Also, duncans seem to react to it by closing up but open right up after the water change. I have a mixed reef. I’ve used it in three different aquariums and never saw them again.