A lot of people get a neon goby when they have an ich outbreak, but they don't realize that nothing will "clean" the ich off of the goby itself... Even LFS's will keep them in tanks that the fish has ich, so it will appear that they don't.
About 6 months ago, my YT got black ich, and after doing some research on this sight, 2 well known advice givers couldn't agree between a cleaner goby or shrimp, or hypo. And since I didn't want to try to catch my tang, I went out and got both the goby & the shrimp. Anyway to answer your question, every mornin' he was slurping up the dots on the tang. He is a very interesting fish and I love his "personality". Every time I vaccuum my cc, there he is cleaning my hands. I love mine, and no problems yet!!! Knock on wood!!!