Ok, first my spiel, not widely-shared in public but heavily shared privately (most people like to avoid the flames, and I'll probably get flamed here by people. Like everything else, people like to justify what they have done.) Beware of Interceptor. I am with the large crowd that sees no thread of redbugs, but Interceptor has a high frequency of being followed by AEFW in massive attack. There is something, IMHO, that Interceptor kills that keeps AEFW in check. That's my .02. Read, read, read before considering using the stuff. And read on AEFW because 95% of those who have had trouble had recently done Interceptor to kill redbugs, though not a soul has seen redbugs actually kill anything. Since it was not your original question, I'll not reply to the inevitable harsh words that will follow ... but since someone advised you to use the stuff I'd like to save you the pain.
I think you are taking the right approach to looking into wrasses. A 6-line is NOT and never has been a good option for controlling sps pests, though for some crazy reason it always appears in such threads. They are aggressive, will kill new additions in the wrasse family down the road, and serve no utilitarian role in a tank -- the only reason to have one is if you find it aesthetically pleasing. But make it the last wrasse addition and ideally the last addition, period.
The Radiant Wrasse (Halichoeres Iridis) is far and away the most reliable attacker of montipora-eating nudibranchs. My view is, if you plan to have montis, you must have a radiant wrasse. And, it is a gorgeous fish.
The Halichoeres Cosmetus (aka Cosmetus, Adorned or Orange-Striped Wrasse) eats AEFW. I know. I did Interceptor then had AEFW almost wipe out all of my acroporas. Since adding the Cosmetus, corals are recovering quickly and zero evidence of further damage anywhere. I got the Cosmetus after reading multiple other reports. Trick is, make sure you are getting a Cosmetus and not a Claudia or a Melanarus. There are clear markings on the Cosmetus, but stores big and small and distributors often confuse these three. The others will control some of these pests as well, but only the Cosmetus clearly eats AEFW off of the corals.
