acans melted away, favia in trouble

So yesterday I came downstairs in the morning to find my acans frag, which I have had for about 2-3 months, had totally melted away, leaving just a skeleton. The day before it looked healthy. My green favia brain, which is in a distant location from the acans, is also starting to peel away from its skeleton, in obvious trouble.

The other LPS and SPS in the tank seem fine.

Tank parameters - amm/nitrite/nitrate 0, phosphates 0, pH 8.0, calcium 460, magnesium 1500, alkalinity 4.5 mEq/L, temp usually ranges 77-81, salinity 1.025.

The things that have changed - my tank had been fallow for 8 weeks and my fish were returned to the tank 2 days before. However, I have been monitoring the tank parameters very carefully and detected no spikes.

Also, the night the acans melted away, I had a thermal malfunction where the temperature dropped from 81 that it had been during the day to 75 degrees at night (usually only goes to 78 at night).

So bottom line question....why the coral deaths? If it was an ammonia spike (which I doubt), why only the acans and favia affected and not the LPS/SPS? If it was the temperature, same question. Any other suggestions? Solutions?

 

have you added anything new in the tank...coral wise or water from another source (LFS water?)

It sounds like it is RTN...even though it typically attacks SPS I have seen it go after LPS in the store

How fast did it die? Was it a matter of a day or over weeks? Also are you feeding those corals? They do like meaty foods

 

It died literally within a 24 hour period - just melted away leaving a skeleton. I thought of RTN, but as you said I have only heard of it with SPS, not with acans/favia.

I spot feed them mysis shrimp a few times per week.

In terms of new things - no water from the LFS. I did, however, add a little water from my quarantine tank to the DT as I transfered my fish a few days before this happened. The QT water has the same chemical make-up as the DT water. I had used Paraguard in the QT, but I was told it dissipates on its own and is removed rapidly with a protein skimmer. I did not think the minute amount of Paraguard in that water, diluted massively in my 90g tank, would cause death. And why just the acans?

 

Do a mitronidizole dip asap. It saved my chalice.

 

I have some metronidazole lying around...but how do you dip in it? I thought it wasn't water soluble? In any case, it's now too late for my favia. It is now a skeleton with green powder in the crevices

Once a coral is a skeleton, is there any chance of it coming back, or should I remove it and throw away the skeleton?

 

It most likely wont' come back, not from that. I had some blastos in my tank and they died, leaving only a little green center, I left them like that for a while and they never came back. It's most likely too late.

 

Uhhhh, maybe it was the "malachite green and fish protective polymers", et.al. in the paraguard?? Or maybe the "Aldehyde blend" (could that be formaldehyde perhaps)?? Just wondering. :

Ingredients: http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=4741

 

Could have been. I am just surprised that the very tiny amount of water I added from the QT would have had such an effect on a total of 110 gallons of DT plus sump water. If it had been copper, I would understand. But paraguard?

In any case, I actually hope it was just the paraguard as opposed to a parasite/bacteria, because that way it won't affect anything else at this point (I did a 30% water change today).

 

Well, judging by your water parameters, and your comments, you seem to know what you're doing. Your logic about the concentration is good. You certainly could be right.

Still, those chemicals are perfect to kill invertibrates. It would be interesting to know the actual concentration of malachite green or formaldehyde required to damage.

Do you run activated carbon? If you don't, maybe you want to try some activated carbon for a while to clean it up just in case.

Did you have any parties lately where someone could have poured their drink in the tank, or anything else that could have happened without your knowledge?

 

Microwave a the water first until it's really hot. It mixes.