George Patterson wrote:
Sounds like ich (oodinimum). Has the tang been going through a cycle of
this? That is, does the tang exhibit symptoms for about a week and then
have no symptoms for about a week? And when the tang has no symptoms, do
there seem to be a bunch of very tiny white dots doing loops in the water?

Maybe. Tang does seem to go through periods when he itches furiously,
but then he doesn't seem to for awhile. Just when I think I should do
something, he seems to get better.

I only see the tiny white dots on the coral beauty. I've looked at the
yellow tang, but maybe it's obscured by the bright color because I can't
seem them.

As for the water and tiny dots, it appears so. I don't have a good
mechanical filter yet, so it's hard to say.

--Kurt