So 2 days ago literally over night my yellow tang had showed up with this reddish brown patch at the base of it tail so I Immediately pulled it from the tank. Thankfully I haven’t broke down the 40g in my garage yet. Well those patches are gone but now it has a white line across its back just below the dorsal fin and behind it’s eyes also look as if the color was just erased. I don’t have a pic of my fish with the patch that went away but I found one online that looks very similar. My tang apparently hates cameras but here’s the best most recent pic of him tonight. I figured stress because of the new fish stole his bed.