Duncan trouble

[logibear]

So thought my Duncan closing up was just it being temperamental until when I just looked and one stalk the tissue just melted or was peeled off overnight. Is this what RTN looks like? I’m new to reefing so lots I don’t know. All of my other coral have been doing great.

 

[logibear]

Bump

 

[logibear]

Going to try one more time. I know it is pretty blue but the green flesh was just completely stripped.

 

[Shirak]

Post a close up in white light and all current tank parameters.
How long have you had it?

 

[logibear]

Can’t get another picture as it got worse so I took it out. Had it for at least 3 weeks and did fine until about 3-4 days before this happened.

Temp 76-77
Dkh 10.5
Nitrate 5
Phos 0.11
Ph around 8

I don’t think this is a water quality issue as all other corals including few zoas, other lps, and some hardy sps as well as 6 fish seem to be doing just fine. It makes me think this is disease of some sort or a pest like a crab which I have many but I really can’t be sure as I haven’t seen anything around it but snails.