Sick M digi--any advice appreciated.

[Gyr]

I bought a small frag of an orange polyped, green montipora digitata from one of my LFS's last May. They called it the 'Firecracker Digi.' I don't know it's lineage, if its from a wild colony or captive propagation. It was doing okay until about 3 weeks ago, when it began having areas of poor polyp extension. These areas have gradually increased in size and become confluent. The base has lost its color, too, becoming a pinkish tan color. I accidently broke this coral 4 months ago, and although in different areas of the tank, both pieces are showing the same signs. All of my other montipora and other corals are doing well.

Here is a photo of one piece before the problem started:

Here is the same piece today. I moved it to my frag rack in a lower light area hoping that would help, but the problem has continued to progress. This photo was taken with a flash, the first wasn't:

Here is a close up, I don't have a good camera so this is the best resolution I could manage:

Does anyone have any idea what is happening, or what I could do to try to save this digi?

My water parameters have been very stable, with nitrate and phosphates at 0 for many months and my alk runs 7 -8, Ca level 400-420, Mg 1250-1350, SG at 1.025, temp = 79-80.

Thanks,
Kurt

 

[Gyr]

Anyone?

 

[preef]

Have you changed anything in your tank lately? Did you start running GFO just before this started? Did you start running lots of carbon in a reactor just before this started?

When my tank crashed last year my digis were the first to show stress and looked similar to yours.

Can you think of anything else that may have changed? Did you dose any meds?

Have you looked for monti eating nudis?

 

[Gyr]

Preef,
The most recent change I have made was that I started to do my weekly water changes via the wet-skim technique. I made this change last October. Most of my M caps bleached a little right after the first wet-skim water change, but they recovered eventually and now look better than ever. The digi's, including the Firecracker, didn't seem affected at the time (here's a link to that episode if you are interested: http://www.reefcentral.com/forums/showthread.php?t=1925210 ). My current Firecracker digi problem didn't start until about 3 weeks ago. I hope wet-skim is not the cause, because everything else in my tank has improved with this technique.

I haven't had any other system changes for the past 6 months or so, which is when I started running BRS GFO and GAC.

I will have to do some research about the monti eating nudibranchs, as I don't even know what they look like. Do they tend to be selective and just stay on one monti? I have many other montipora in my tank, including several colonies of a purple digi and none of them are showing any problem (at least not yet). Here's a picture of 2 caps and 2 digis (and a bird's nest), all looking healthy.

Thanks for your help, I'll let you know if I figure out what the problem is. Would it be best to keep the piece in less intensly lit part of the tank for now?

Oh yeah, I did treat my tank with Interceptor for red bugs. The final round of interceptor went into the tank on October 11th. No apparant affect on any of the corals.

 

[Gyr]

Okay, I read a little about Monti eating nudibranchs. Pretty scary. I spent a big chunk of the afternoon with magnifier and macro camera shots. I don't think my problem is nudis, but that may just be wishful thinking.

Here is one of the best macro shots I could get with my camera. It is of the transition zone of the sick and still somewhat healthy looking areas of the coral.

From what I could find out, the nudis apparantly eat the skin completely, exposing the skeleton. My Firecracker still has the skin, but it is discolored and no PE. Maybe that's just the early stage of nudis?

As I said I spent alot of time searching for bugs/nudis and this photo is the only one that had a possible sighting. It may just be a piece of mucus or something, but I am not sure. It doesn't look much like the nudis I saw photos of on other threads (the exposed skeleton on the bottom of photo is where I broke a tip off getting it out of the tank):

So does anybody know what might be going on?

Could it be the Montipora eating nudis? If so, I'll throw the Firecracker out. I'd hate to do that if not needed, as I liked it when it was healthy.

Thanks