Only 3 sure ways to cure marine ich . Cleaner fish or shrimp are not one of them .
3. Transfer method
Those are the only three ways to cure marine ich no matter what anyone else says.
It is a horrible disease in the marine aquarium in compare to its shared name freshwater disease. FW
ich is a walk in the park .
Marine ich has been documented to have a life cycle of up to if not over 90 days and has devastated many tanks almost completely...
If you have it these methods are all that will work. If something else works it is not marine ich.
Here is a link to confirm where I get my info and opinion from...
Sometimes fish just scratch. Look for spots in the am as the ich will fall and multiply where the infected fish sleeps and re attack it nightly .I know some say lights out for ich [which is silly because ich does not have eyes] but if it is bad I have left my lights on 24/7 during treatment...