GSP opinions/help?

[sharuq1]

I noticed that the tips of my GSP were looking blackened so I looked for a cause. I found these little snails on my GSP. On further observation I noted they are ALWAYS on the GSP and nowhere else. Looked to me like they were snacking on it. I had read you could do a 10 min. FW dip on coral for these kinds of problems and I did but now the GSP looks terrible. The polyps will not even come out at all, and the purple looks less purple. Did I kill it??