What's eating this coral?

I'd love to have an ID on this coral disease my red planet has had for a while. It has slowing been eating away at the skin and leaving sandy rubble behind. It appears to be spreading to the montipora caps nearby.



Other corals are doing well and a montipora cap on the other side doesn't have this. Water parameters are alk 4 meq/L, cal 520, mag 1400+.

Any ideas on what this coral disease is and how to treat it?

 

It's been a while since I looked at these sites and maybe you have already done the same type of search, anyway here a few links.

The sandy rubble has me puzzled the most. Is the skeletal structure just breaking down and leaving the substance or is a pest leaving it behind after feeding.

Since you're an old hand at this I image you have already tried to view the tank/corals in the middle of the night already. Looking for Asterina stars or Nudibranchs or even some types of Limpets.

Is it even possible to frag an infected piece and dip, secure it again and see if the condition continues?




NOAA's Coral Reef Information System (CoRIS) - Major Reef-building Coral Diseases
Coral disease

 

My self proclaimed expert googling skills only came to this http://coraldisease.org/diseases/16 however it says two weeks and I assume this has been much longer?

 

Aye thanks Cheryl I did go to that disease page. I don't see an exact match from that, a bit like White Pox perhaps.

I have tons of asterinas, I'd never see a nudibranch or limpet though.

The red planet is on a loose rock, I could do a lugal dip with it and that thought has crossed my mind. But I'd love to know what I am dealing with first.

matt

 

Yeah it has been longer. That does sound like it has similar conditions though. Thanks for the link!

matt

 

How's the flow in those spots. I've found that flow dead zones can cause food and detritus to collect on Monti's and cause a similar effect.

 

You might also be having problems with your Ca and Mg being so high. Having those two above the recommended range can cause the coral pores to get blocked causing necrosis.

I would lower the Ca to no higher than 450. The Mg you can get away with it being where it is at but lowering to no higher than 1350 would be good.

I think you are looking at a combination of Jason's and my suggestions by the locations of the losses.

 

THanks all.
I just did a water change yesterday. I'll try a dip on the planet and lowering calcium more. Not sure what is going on with that planet, but, as shown in the pics, the caps are plating on the ends and graying out in middle. If a flow thing, perhaps it will migrate and even out?

 

My montis grey out the same way. I thought it was too much light because when I threw it under some rock in the corner it started growing very much.

 

My red monti has a spot that looks the same as yours. I noticed at night a bunch of hermit crabs congregate there and spend the night. For some reason they all go there. Have you ever noticed crabs sitting there at night after lights out? They stay until morning. No other corals show any problems. the patch isn't getting anyworse but its not getting any better either. Could it be caused by crab poop?