If you bought an animal and didn't quarantine it for a month before adding it to an established tank, you've made a serious mistake
. Your statement that you don't have a tank that you can use as a hospital tank implies that you don't have a tank you can use as a quarantine tank 8O. Who failed to advise you about the importance of quarantine? Which book did you read about fishkeeping that didn't repeatedly emphasize how necessary quarantine is to the health of your fish?
I hear this kind of thing all the time: "I just bought a [FAV BREED HERE] and now the fish in my tank are sick! Help!" To me, an equivalent story might be: "I just bought a gun, loaded it, pointed it at my foot and pulled the trigger and now my foot hurts a lot! Help!"
What were you expecting?
Look, I'm sorry for being so harsh, but I don't see how a responsible person can enter this hobby in this day and age and not have heard about the importance of a simple quarantine for additions to the tank. And if you've heard about the importance of it, why aren't you doing it? As pet owners, we are responsible for the well-being of our pets. Just as much as you wouldn't starve or beat a puppy or kitten, you should provide an environment where the fish in your care can be safe, healthy, and comfortable. In my opinion, quarantine is step one in fulfilling that responsibility.
If you feel like answering a question after that, I'm honestly curious if anyone told you about the importance of quarantine and if so, why you haven't been practicing it?
As for how to solve your problem: your fish has marine ich (which your tank now has). The black critters are something else, perhaps flatworms. To treat the ich, set up a hospital tank and remove all fish from the reef tank for 4-6 weeks (to cure the main tank). In the hospital tank, there should be no sand, use PVC to build some terrain that will make the patient(s) comfortable, treat with one or more of methylene blue, copper sulfate, hyposalinity, or freshwater dips depending on the specific fish you're treating. Myxazin is snake oil good for adding $$$ to LFS profits. For your tank, it's worthless.
Sounds like a pain in the butt, right? It is. And that annoyance is exactly why quarantine is so important.
To treat the black spots, try to get a high quality photo and post it to the forums so that the experts here can help ID the problem, if a cure is needed (many times, population imbalances will naturally correct), they ought to suggest it at the same time.
Be warned, the advice above is very cursory and will get you headed in the right direction but probably isn't enough to do more than get you asking the right questions. Treatment of aquarium fish maladies is a book-sized topic. I'd really recommend building up a good library on fishkeeping, including reading the entire archives of this magazine (
http://www.advancedaquarist.com) and Reefkeeping (
http://www.reefkeeping.com).
Good luck,
Ross