You need to quarantine your new arrivals in a
separate quarantine tank.
You've just introduced this pathogen into your entire display...and now you have a fight on your hands.
Garlic will sometimes help control ich, and there is anecdotal evidence that it can sometimes aid in curing it altogether. Most success stories are about hardy fish species, usually established in a system, that have a fair chance of fighting off the parasite on their own anyway. I wouldn't trust garlic to cure a newly added angel. A cleaner wrasse is also not a solution.
I deleted the part of my post where I chewed you out, I'll just say that
Proper quarantine procedure is one of the most basic components of successful marine fish keeping. Quite frankly, if you don't change your ways, you're in for a load of frustration.
I suggest you start here.
http://www.marineaquariumadvice.com/aqu ... ish_1.html
And read all the way through part Five, you can get to them through the index, here
http://www.marineaquariumadvice.com/library.html
I do believe I posted to you in another thread about what this fish requires to establish itself in a tank...stocking order and whatnot? You've opted to add another anyway, and the chances of this fish establishing itself in your system, with the current established species, and with you once again providing it with an uphill battle, are less than great unfortunately.
My last post to you is below...
Fish of this genus, while not the most delicate in the hobby, still require you to treat them with the utmost care and consideration when introducing them into a new environment. You have to do everything possible to mitigate possible problems and give them every chance to acclimate and establish themselves in a system. This means practicing proper quarantine procedure when first getting them home, and in general, introducing them first (whether initially, or after a tank upgrade) as stated before so they can properly gain a foot (fin) hold.
Sorry for my bluntness...but it is what it is...I find this sort of thing endlessly frustrating.
I guess I ended up chewing you out a bit after all...sorry.
