White spot on montipora

[Zvejkus]

Hello all,

I would like to ask you for some help with identifying my problem. I have nice yellow/green branchy montipora. It was growing(and still does) like hell and was so nice. But it is about two weeks ago, i observed big white spot on it, place without polyps. I though, it might be crab or something. But I never saw any on it, even during my night checks. Please, can you give me any suggestions, what it could be?

Sorry, I appologize for the quality of my pictures, just did my best.

General view:

Detail:

 

[MechEng99]

Since it's in the center of the coral, it may be a spot with too low of flow or not enough light.

Or...you could have Montipora-eating Nudibranchs. I don't see anything that obviously looks like one in the spot above, but check anyway. They're nasty buggers. Might be a fish or something else nipping.

 

[S.A. Trev]

I had the same issue with my Acropora and it turned out to be STN and I am 100% sure yours is the same problem its caused by sudden changes in water parameters and mine was cuase by running my external skimmer 24/7 and it was the sudden drop in nutrients which caused it

 

[Zvejkus]

MechEng99, S.A. Trev, thank you very much for your answers.

Well, its true, I added new phosex and active coal last weekend, so the water should be a bit different than it was before. But I don't think its cause of this, cause the spot was there before this change.

Here are my water parameters before the change:

Salinity: 1.025
kH: 8-9
Ca: 420
Mg: 1320
NO3: not detectable
NO2: 0.1
PH: 8.1
PO4: 0.03
NH3/NH4+ : 0.25

Now it should be better with NO2, NO3 and PO4.

Possible problem could be also Gobiodon okinawae, but other corals look ok with him and he never nipps SPS(one of the good boys).

I am sorry, but have little problems with US abbreviations. STN is a kind of necrosis, if I understand it, right? Is there any way to cure that necrosis or should i frag the coral to save it?

 

[reefWW96]

this is natural for corals in the wild too, as the colonies grow bigger the lower parts dont do as well since they get no light. You dont have to worry about it unless it starts spreading.

 

[MechEng99]

If you added too much phosphate remover at once, it could cause this if it started around the same time you added the remover. But, the location of the white spot makes me think flow, lighting, or...as you just mentioned...your Goby.

Some people never have a problem with those gobies, but other people do. They don't often cause mass damage - just take out a few polyps to make their nest *just right*. Is he often near that area?

The photo looks to me like physical damage to the coral - not just tissue missing...which makes me lean toward flow & critter damage. Any other inhabitants that could cause this?

 

[mm949]

looks like a colony of nudi eggs....if so remove the coral and hope they havent spread

 

[Zvejkus]

mm949: how do i recognize that there are any nudi branches or the nudi eggs? With my eye I don't see anything on that place.

MechEng99: Well, its true, that I firstly added phosphate remover last week. About a cup(200g/250ml) for my 70g/250L tank. About the flow, the flow didn't change for months, so I think its not the cause of this problem.

 

[mm949]

they lay the eggs in a linear position like little strands on beaded thread, white in color

 

[Zvejkus]

I cannot see any eggs there. I have quite good eyes, but cannot see any nudies or eggs. The original white spot is looking like it wants to regenerate. But there are two more spots about 1 inch left from the first one. They appeared yesterday and today are much bigger.

 

[losthere]

If you cant get the monti out to dip. Set your alarm for 4am or so and take a look at your tank with a flashlight, if you have M.E.N. there is a grater chance you will see them feeding at night.
It does look like M.E.N. damage though.
Good luck.

 

[Zvejkus]

losthere, what does M.E.N. mean? nudi branches, crabs?

 

[losthere]

Montipora Eating Nudibranchs=MEN

 

[MechEng99]

That's starting to look like Nudi damage to me. I don't think phosphate remover will do anything like that.

Do you have any other montipora in the tank? Any changes in them? I'd get that Monti out (if you can) and examine it with a magnifying glass.

 

[Zvejkus]

I have four other montiporas in my tank, three of them just few inches next to the damaged one. No damage visible.

Yesterday evening I fragged and removed the damaged part of the montipora. Now I will wait, if it will be ok or not.

Is there any cure recommended in case you are right and there are MEN? Does help dip in lugol's solution or something?

 

[MechEng99]

As far as I'm aware, potassium permanganate is the only thing that will kill the nudis AND eggs (someone correct me if it's not an ovacide). The adults take quite a while to kill in dips. Lugol's killed the adults I had on a frag, but another time, CoralRx didn't do anything to the adults. Those are the only two I've tried.

The eggs are usually laid in dead areas on the base of the coral, in tissue folds of the coral, or in areas where the nudis have already caused damage.

I've never had to deal with MEN long term (they came in on frags twice, so I threw the frags away rather than dealing with them). But, you may be able to break the life cycle by killing the adults with dips and keep dipping until all the eggs have had time to hatch and be killed by the dip. See some of the stickied threads for more info.

Still not convinced you have MEN, but not sure it's something else either.

 

[Zvejkus]

Thanks for advices MechEng99. I removed the damaged parts of the coral and threw away. I watch the rest of the montipora, and pray, I removed all the nudis. Today I didn't see any new damage, but it is still too early.

One more question. How strong should be the lugols solution? I have just the tropic marine Iod/Iodid lugols solution, i give as one drop with bulb pipette into my tank daily. I think its too strong to dip the frags in it.