What's wrong with my Acropora(s)

[ThRoewer]

This evening I noticed that one of my Acropora frags had in some areas "lost" it's tissue. Under the microscope it looked like it just peeled off.
I couldn't see any obvious predators and the skeleton had no algae growing on it yet.

I didn't notice anything being wrong with it last night or this morning.
It's been in my tank for about 2 months.

This is it today with one branch completely "skinned" and another missing a patch:

This was it a little over a month ago:

The green Acropora frag to the left of it is now dying slowly after being in my tank for 3 months. In those 3 months it only grew a bit on its base but never on the tip. Two weeks ago its base polyps started to expel their intestines and then started slowly to recess and die.
This one shows some microscopic organisms in the craters of the recessed polyps that look like ciliates that seem to eat the Zooxanthellae the polyps expel.

Both are not expensive or irreplaceable pieces but I better find out what is killing them before my less easy replaceable pieces get affected.


Lightsource: Kessil A360WE Tuna Blue, Imax: 100%, Cmax:

Last water test results:
Temp.: 24.7 °C (controlled by my APEX following the season table)
pH: 8.1 - 8.4 (measured by my APEX)
Salinity: 34.7 ppt (measured and controlled by my APEX controller)
Alk.: 12.1 dKh
Ca: 550 ppm
Mg: 1380
Phosphate: trace
Nitrate: 2.5 ppm
I'm dosing Bionic 2 part solution and Kalkwasser

 

[Decalf]

Whats wrong

Whats wrong

Do you normally run your DKH so high? Seams higher than most sps tanks run these days. Not saying this is your issue but might be contributing

 

[tdb320reef]

Cut the dead branches and treat iodine in the wounds.

 

[Reef Bass]

I think I see a lot of bite marks in pic 1.

 

[ThRoewer]

Do you normally run your DKH so high? Seams higher than most sps tanks run these days. Not saying this is your issue but might be contributing

It isn't really my intention to have it this high but rather a side effect of the Bionic 2 part solution. I already cut Part 1 down to 50% of Part 2 but the DKH still continues to creep up.

Cut the dead branches and treat iodine in the wounds.

Overnight more tissue peeled off. I think this one is a gonner and all efforts to save it are futile.

I think I see a lot of bite marks in pic 1.

Can you point out which the suspected bite marks are?

Is there any reference page for coral diseases and parasites? I mean something with pictures or even videos that give you an idea what to look for.

I have a binocular microscope that can get up to 90x, so I can do a thorough inspection of all my corals but I would need to know who an evildoer is and who is just an opportunistic feeder on already dying tissue (basically clean up crew).

On the slowly dying coral I noticed something that looked like ciliates and were hanging out around the retracted poly mouths, and even inside the mouth openings. They seemed to be feeding of expelled zooxanthelae.
Another one looked like a flagellate, but all green, oval shaped seen from the side and flat from top.
I have seen the same guys on a decaying yellow Parazoanthus colony.

 

[JammyBirch]

It isn't really my intention to have it this high but rather a side effect of the Bionic 2 part solution. I already cut Part 1 down to 50% of Part 2 but the DKH still continues to creep up.

When you use a 2 part you use the alkalinity to determine the dose not the calcium... So your alk should always be right on. Do you dose Mag?

I use B Ionic 2 part also, and dose mag. My calcium always seemed different and hard to maintain a constant level, that all changed when I started dosing mag.

Actually all of you levels look high to me, I don't think going over 1350 for mag is good either.

 

[toothman]

oh my, stop dosing for a bit

 

[ThRoewer]

The test results above where from last week, tested at the LFS (they use Salifert).
After those results I already reduced the daily dosage from 12 to 10 ml a day and today I reduced it now again to 8 ml.

I also tested KH, Ca and Mg today with my Red Sea kit and these were the results:

KH: 10 dKH
Ca: 500 ppm
Mg: 1320 ppm

Still high, but the info in the Red Sea kit suggests 12.6 dKH, 465 mg/l Ca and 1390 mg/l Mg to accelerate growth of SPS frags. Based on that only my calcium would be too high.

I somewhat doubt that high, but not crazy out off range KH, Ca and Mg levels cause an Acropora to just jump out of its skin.

Also I have a Porites (a hitchhiker on a live rock), a Montipora capricornis, several different Seriatoporas and even some acroporas growing pretty good. Same goes for all my LPS which are growing well.

I looked at the peeling coral under the microscope and can't see any flatworms or copepods on its surface. I'm not even see the ciliates that where on the slowly dying coral. So if it is some parasite it must be internal.

 

[Bezz]

From my personal experience, everytime my Alkalinity gets above 9.5 dKH, my SPS starts acting funny. I found that there is a much smaller margin for error when Alkalinity is high, than when I keep it between 7-8 dKH.

 

[kevin_e]

Do you have a lot of hard coral growing? If not, I'd stop dosing kalk and bionic as its unnecessary. Most is probably precipitating anyways.

 

[Pife]

I somewhat doubt that high, but not crazy out off range KH, Ca and Mg levels cause an Acropora to just jump out of its skin.

You saying this tells me you haven't had sps for long. That alk is high. That might not be your problem though. Do you do your corals?

 

[ThRoewer]

Do you have a lot of hard coral growing? If not, I'd stop dosing kalk and bionic as its unnecessary. Most is probably precipitating anyways.

I have a lot of coralline growing all over the rocks, tank walls and equipment. And several corals, mostly the Seriatoporas, Porites, Montipora and Blastomussas but also several of the Acroporas grow well

I switched the 2 component dosing pumps off for now and just continue a small amount of Kalkwasser. Let's see what that does.

You saying this tells me you haven't had sps for long. That alk is high. That might not be your problem though. Do you do your corals?

I had some SPS and LPS back in Germany in the mid 90s, but back then the only things we were adding were Kalkwasser, Strontium and Iodine.
I haven't dipped my corals yet but the store I buy them from dips all their corals at least once a week.

About a week ago I got Coral Rx but have only tried it now on the sick corals. And while the coral didn't like it (I used a pretty hefty dose - 2 drops on 50 ml) the little critters on it seemed completely unaffected.

Which dips are actually effective against all the coral pests out there.
What beyond AEFW, nudibranches and red bugs is out there on coral diseases?

I'm asking because when I looked at the slowly dying coral under my microscope there was a multitude of critters populating it, including some clear nematodes.

And last night I took the peeling coral out of my tank and put it in a glass jar with some tank water. I couldn't find any parasites on it. But when I looked at it this morning the water in the jar, the bottom and the dead coral were swarming with something I would categorize as ciliates that had their bellies filled with little green spheres (zooxanthellae?). I also found the clear nematodes again.
Are these pests or just the cleanup crew?
And did they multiply that fast or were they already inside the coral?

My current tank is going to be upgraded to a larger one soon and anything will be dipped, quarantined and thoroughly inspected before going into it.

 

[Aqualund]

It took me several weeks to finally realize how to identify Acropora eating flatworms. It took a glass container over a black surface and dipping with coral revive...to finally see some fall off after 10 minutes. otherwise they are impossible to see.

 

[Sawdonkey]

This looks like RTN/STN due to water conditions rather than a pest.

 

[ThRoewer]

This looks like RTN/STN due to water conditions rather than a pest.

What's RTN and STN?

My guess was also that something is off, though I suspected the light as the smaller, slowly dying one was first affected at those areas that were perpendicular to the light source.
Didn't think the alkalinity would be too high since it was still below the levels recommended for growing frags by the Red Sea test.

The other thing that is worrying me a bit are the relatively large pH and ORP swings. Though those seem to be rater connected to the light cycle:

 

[Aqualund]

Those "swings" are normal daily ranges for a reef tank.

RTN is rapid tissue necrosis and STN is slow tissue necrosis. (tissue death). The eggs from aefw can cause both when they hatch.

 

[71xlch]

Those "swings" are normal daily ranges for a reef tank.

RTN is rapid tissue necrosis and STN is slow tissue necrosis. (tissue death). The eggs from aefw can cause both when they hatch.

Doesnt look like AEFW at all to me. If you take your frag out and let it sit in the air for 15ish seconds under a strong light the worms become visible. Turkey baster in a small cup of water will blast them off as well.

Only time i have had STN and skin peeling off is when my parameters where out of whack.

If it was AEFW you would see alot of these on the non dead parts:

http://smg.photobucket.com/user/impur/media/need id/P6020154.jpg.html
http://s64.photobucket.com/user/flyyyguy/media/pests/bitemarks.jpg.html

 

[ThRoewer]

I know that pH fluctuations are normal due to photosynthesis consuming CO2 during the light period. But my pH level currently swings between 8.1 and 8.4, which is quite a bit higher than what I had in my previous systems where it usually fell at night slightly below 8. So I'm wondering if I should add some CO2 during the daytime to keep the pH below 8.3.

I looked a these corals under a microscope. While AEFW may be hard to see, I would have seen them if they were there, no matter how hard to spot they are. I also did not see any of these bite marks.

What I saw under the microscope at the slowly dying coral were several types of micro organisms populating the mouth area of the polyps - the same types of organisms I saw on my "melting" Parazoanthus spp. polyps.

I did not see these in significant numbers at the peeling coral. Though after I removed it from the tank and let it sit over night in a glass jar I found massive amounts of them all over the jar, munching away on the expelled zooxanthelae. They where either inside the coral or must have multiplied like crazy over night.

So the thing that concerns me more right now is the possibility of internal microbial or bacterial coral diseases. Bacterial diseases are known from anemones and I just found out that there are also parasitic protists for corals.