Nice rubber band! (Couldn't resist from your other thread.. anyways..)
It does look like fungus to me. Def keep up on w/c as that is always a must.. but adding some salt might be beneficial.. or perhaps doing a salt bath on him.. might work a little better.
You said he'll spaz at times.. what exactly is he doing? Darting around? Shaking? Swimming funny? I am sure all parameters are fine? How long has he been like that.. do you know?
Amber