My yellow tang recently got the black spot disease. How can i cure him? Will the cleaner shrimp i have cure it? whats the easiest to do? I heard giving it a freshwater bath will work but what about copper? Also i have a blue hippo tang should i cure him too i do not see any on him but it seems to scrap and scratch against the rocks lately.

Don't panic as much as you would with white spot, its not as detrimental to their health.
Majority of the time it will clear itself.
Keep the immune system up with crushed garlic. And keep regular water changes happening.
I have been told that tri sulfate tablets from the fish shop helps as well,
good health it will eventually go by itself