Help ID: RTN on my acro?

[cgill311]

I need some help from the experienced SPS guys. Is this Rapid Tissue Necrosis (RTN) that's happening on my acro? It appears to be dieing from the base up. The flesh is just melting away. Am I correct in the only thing one can do to save the coral is to frag it ahead of the RTN? Are the palys killing the acro? They were doing fine together for so long.

My temp is very stable 77F. pH = 8.03 (normal for my tank). Alkalinity about 240-300 ppm. Salinity = 1.024. No ammonia, nitrates. I've also noticed in the growth in the number of flatworms in my tank.
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[skriz]

If the flesh is melting away, it's RTN. Frag it. Leave about an inch of living tissue on the dead part and cut.

If it continues to RTN, frag it into smaller frags and hope that some will survive. You can reattach the frags somewhat to form a little colony again...

 

[jmaneyapanda]

Before we jump to any conclusions, what could be close enough to be touching it? I see a leather, and if the waxy sheds are landing on that parts, it may be problematic. If it is impossible that something is touching it, I would listen to SKriz.

BTW, I would not call it RTN, though. RTN will wipe out the colony in less than 24 hours.

 

[cgill311]

jmaneyapanda;156006 wrote: Before we jump to any conclusions, what could be close enough to be touching it? I see a leather, and if the waxy sheds are landing on that parts, it may be problematic. If it is impossible that something is touching it, I would listen to SKriz.

BTW, I would not call it RTN, though. RTN will wipe out the colony in less than 24 hours.

I have a small tank, so my reef real estate is very limited. The acro has been touching palys, yellow colony polyps, and a neon green toadstool leather for some time now without any issues. Yesterday, I looked at the acro, and all was fine. This morning I check my tank, and half of the flesh (starting from the base) has melted away. You can easily see the white skeleton and holes where polyps used to be. I ended up fragging the healthy portions about 1 inch above the dead portion. Maybe some of the frags will survive.

This really sucks b/c it was the first acro I bought a few years ago from Melissa. It was brown for a long time but has recently colored up to a beautiful pink color. Polyp extension was fantastic, growth rates were good, and the colony was just starting to fill out and look really nice.

Then half of it dies in under 24 hrs. :sad:

Will flatworms bother an acro? I've noticed an increasing population over the past month. I also just bought an emerald crab 2 days ago. I wonder if it had anything to do with it?

 

[cgill311]

Also, will RTN spread to my other SPS? I have a small colony of mojo's green slimer and some other SPS nearby.

 

[calireefer]

You might want to take a couple frags just in case. I had some digitata RTN on me once it was a definite line from dead to living tissue. hard to tell from the picture but yours looks more bleached out. Have you changed anything lately; Bulbs, photo period, carbon, maybe even a large water change or another coral that was shading this one.

 

[FutureInterest]

If the death starts from the base its serious and is typically RTN. Bleaching usually starts from the tips and is treatable. You did the right thing by being careful and fragging it as you did. Hopefully, the remaining portion will be just fine. I agree with the above posts that you should do some WCs as something seems to be amiss.

 

[sammy33]

CGill311;155957 wrote: Alkalinity about 240-300 ppm.

This is a range between 13.4 to 16.8 dKH? That seems high to me IMHO.

I have recently (last few months) been targeting NSW values around 7-8 dKH (~135 ppm) for alkalinity. I think some of my previous problems with bleaching and tissue necrosis were caused by my higher alk at around 11 dkh. Since I have lowered my alk I have had far less problems with my SPS.

JMO. Hope this helps.

 

[cgill311]

sammy33;156160 wrote: This is a range between 13.4 to 16.8 dKH? That seems high to me IMHO.

I have recently (last few months) been targeting NSW values around 7-8 dKH (~135 ppm) for alkalinity. I think some of my previous problems with bleaching and tissue necrosis were caused by my higher alk at around 11 dkh. Since I have lowered my alk I have had far less problems with my SPS.

JMO. Hope this helps.

Dunno...it's hard to read those little color charts.

 

[calireefer]

I just looked at your pictures again and I bet it's that green slimmer thats doing it. I have a motipora cap near my green slimmer and one day some slime got on and killed of a good sized area.