help me figure this out??

[danmar26]

I haven't dealt with a parasitic infection in over 6 years. 120 gallon reef. Last year I added a few fish from a privately run fish distributor who wouldn't sell his fish until they went through an extensive quaranteen proceedure with medication. Fish were added directly to my DT without any parastic issues. Unfortunately he is no longer in business. This year I added 2 fish from local fish stores. They were added after a 2 week unmedicated quaranteen period in a 10 gallon tang. In retrospect I know I messed up by not proactively medicating. They looked fine and were eating well. Upon adding them to my tank, they(carpenter wrasse and male lyretail anthias) were harrassed into hiding. The wrasse came down with ich and was scratching. After about 2 weeks the harrassment stopped, the fish was now out eating and the spots were gone. No other fish seemed to be infected. 1 month later the fish vanished in the rocks never to be seen again. 3 other fish started scratching but show no signs of ich spots. It's now been 2 months, same fish scratching with no signs of ich spots. Been feeding Dr. G's anti parastic food with no results. Fish also seem to be shaking their heads along with scratching. Was thinking flukes? If it were ich, wouldn't it have showed on the fish after 2 months?Thanks in advance.