Multiple torch colony partial flesh loss

[UnnamedReef]

I have three 10-20 head torches in my tank, had each for several years. Two weeks back my Aussie's center section went down with BJD so I cut off the 5+ heads that I had to in order to remove the infection. Iodine dipped and returned to the tank, but I noticed there are gaps in the flesh bands which I thought was very odd. Not complete recession of the band, but actual circular and linear sections where the flesh is missing.

I picked up one of my indos today to move it slightly (a few heads aren't getting a lot of light since they've grown off the colony to the side) and I noticed similar linear sections of missing flesh, almost to the skeleton so I'm now concerned to see that. All torches open normally in the morning and close down at night. None are getting excessive flow, they've been in the same conditions for at least 7 months each when I transferred tanks.

Parameters:
Alk 8.7
Cal: 442
Mag: 1452
NO3: 5
PO4 .13

As tested this morning. I recalibrated my Trident to make sure nothing was wacky. I did two 25% water changes over the past week post BJD and everything seems happy. My largest indo colony is unaffected.

I have observed my peppermint shrimp picking at torches in the past, but not any time recently. I feel like if I had a parameter/light/flow issue I would see even recession. Anyone seen anything like this before?

First photo is the Aussie, remaining photos are the affected indo

 

[UnnamedReef]

Got my Aussie to close for a better photo showing a circular section of missing flesh

 

[Fish Fan]

This might be a good question for @Rocks reef if he has a minute to take a look

 

[UnnamedReef]

Thank you for the forward!

 

[resortez]

Your parameters have stayed at that range for a while???? Any new additions to the tank???? Any change in routine or husbandry practices???? Asking question to try to deduce the source of the problem. Only thing I can think of, if you’re not doing it already, is dosing iodide into the tank, helps in promoting healthy flesh growth on coral.

 

[UnnamedReef]

Yup, I have Trident dosing so things stay pretty stable. I test NO3 and PO4 every week and haven't had any large swings.

Only additions were a two diamond gobies, a yellow tang, two flasher wrasse, and a fire fish from Dr Reef's a couple months back. Nothing I would really expect to munch on torches

 

[UnnamedReef]

I don't dose iodine, but I never have either

 

[UnnamedReef]

Also, I am sending in an ICP test to see if something wacky is going on. Hoping to get ahead of this if someone out there has seen uneven flesh loss in otherwise healthy looking torches