Hello Tench1
My tank was badly infested with nudis 2 - 3 months back.
When you can see them on your tank wall, that means the situation is quite bad already.
Most of your zoas should be half opened now..
Would suggest as what the folks here mentioned. take out the zoas and dipped them in coral RX.
Else you would risk losing some of your zoas colonies. I did.
I agree it is rather troublesome to remove your zoas and dip them but it is better to get it done at this stage.
Take the opportunity to dip all the rest of your corals too.
When all is done, then add in the yellow wrasse and hopefully he can help clear the nudis population then.
Oh yah, pls remember to dip all your new additions regardless whether it is from LFS or fellow reefers.
I dipped all my corals once, then throw in a yellow wrasse and about 3 - 4 weeks later, dipped those zoas which does not seem to be opening well again. Now everything seemed ok.
for your reference, I did record this encounter in my tank thread - somewhere around page 170 +/- 10 pages.
Good luck bro.
rgds
Jacky