What?

[Hunchback]

I have a millie colony that just all of a sudden started losing all the flesh on it when yesterday it was just fine and had the polyps out. Any ideas?

 

[Matthew_sample]

I would look for a colorful looking snail yellow and black... or another type of bug...
Assuming your parms are right

 

[Hunchback]

I think your thing of a Sundial snail, they feed on zoas, all params are stable

 

[Drew]

Definately sounds like its RTN'ing. I would guess its becuase of the tank overheating because of these last couple of days that have been so warm. Unless you have a chiller set at only a 1 degree swing, then the tank has probably jumped in temp 3 or 4 degrees in the past couple days, and that will cause acro's to RTN.
Hope this helps,
Drew