Is it Ich? (and to treat or not to treat)

[MrTuskfish]

I am wondering.......
Seachem Metronidazole for internal treatment of ich makes sense. In medicine we use Metropolitan to treat protozoan infections as well as amoebic infections.
Cryptocaryon irritans (also known as marine white spot disease or marine ich) is a species of ciliate protozoa that parasitizes marine fish, and is one of the most common causes of disease in marine aquaria.
Since ich is a protozoa, it should respond to Metronidazole.
Using Seachem Focus, which also contains nitrofurantoin, an antibiotic to help any secondary infections, to bind the Metronidazole to the food for internal usage should treat the attached protazoa and kill it at that stage.
If you use it all thru the life cycle, any protozoa that attch the fish should die and effectively rid the tank of the infection.

Ich parasites bury into the fish, they do not just attach to the fish; I assume this is why short-term meds in the water column don't kill it. I have used Metronidazole several times (not for ich control) in an HT. It did nothing for the ich in the fish. I imagine I've seen a few dozen threads on our forum that talk about using Metronidazole for ich; never heard a success story.