Is Recovery of RTN Possible?

[fishgeeksrus]

I went to the LFS today to pick up a spotted mandarin and found these to guys in need of some help. The owner let me have them for $10.00 each. I figured I could stand to loose $20.00 if that is the way it went. It looks to me that they may have RTN. Is this something that they can recover from?

[Ninong]

I will not address the question of whether or not the corals pictured have RTN because I can't see them all that good to be sure. I will make the following suggestion: NEVER place a coral that you suspect might have RTN into your tank with other corals!

[fishgeeksrus]

obvisously I do not know a lot about RTN. I just assumed that it only effected that specific coral and wouldn't transfer over to others. Does this happen?

[Ninong]

Sorry, I forgot to address the second part of your question: The usual remedy when one suspects RTN is to remove the coral immediately and frag off any good parts and discard the bad parts.

There is still no agreement on exactly what causes RTN or even exactly what it is. There is agreement that it is rapid, it spreads and it can wipe out all the SPS in a system in short order.

[fishgeeksrus]

How do you know if it is RTN? I didn't know what was wrong with these corals. OH CRAP!! Did I make a huge mistake?

[Ninong]

How do you know if it is RTN? I didn't know what was wrong with these corals. OH CRAP!! Did I make a huge mistake?

RTN (rapid tissue necrosis) is usually black. It shows up as a black band around the coral that grows rapidly. It is rapid deterioration of the coral tissue caused by enzymatic action triggered by a breakdown in the immune system's defenses. Whether it is caused by a virus (possibly) and, if so, which virus is still being debated.

I believe Eric has some pictures of Acropora infected with RTN in this article: http://reefkeeping.com/issues/2002-03/eb/index.htm

[fishgeeksrus]

I am just not sure if this is RTN. It just looks like it is bleaching. The LFS has only had the aquarium that it was in up about 2 mths. I just assumed it was because of that and he knows nothing about sps corals.

[Ninong]

Never place an animal of any kind that you suspect might have a disease into a tank with healthy animals. This is especially true when it comes to SPS corals. Many hobbyists will not even consider wild-collected SPS specimens because of the possibility of introducing an unknown pathogen into their tank. Too many have learned the hard way from experience that you have to be extremely careful with wild-collected SPS.

I once purchased a couple of SPS pieces that I thought were aquacultured. It turned out that one was and the other was not. However, both the aquacultured piece and the collected piece came from the ocean because the aquaculture facility was in the ocean, not in a tank. I decided to dip both pieces in an iodine bath for 15 minutes just to be on the safe side. I usually do not dip frags from other reef tanks.

My advice again is to never place any coral that you think is diseased into your tank. If you have a separate hospital tank, use that. Otherwise forget about it if you think it is diseased. If we are talking about a frag from someone else's tank that was touching another nearby coral and is therefore damaged by aggression, that's different.

[fishgeeksrus]

Should I take them out? or is it too late?

[Ninong]

I am just not sure if this is RTN. It just looks like it is bleaching. The LFS has only had the aquarium that it was in up about 2 mths. I just assumed it was because of that and he knows nothing about sps corals.

I don't see anything that looks like RTN either but I don't want to disagree with you because I'm not the one holding the coral in my hand or at least looking at it from just a few inches away.

Bleaching can be caused by many different factors. Usually when we talk about bleaching, we are talking about the lack of zooxanthellae that resulted from an intolerable environmental condition of one sort or another rather than something caused by a pathogen, although some cases of bleaching are attributed to bacteria.

[Ninong]

Should I take them out?

That's up to you. I'm afraid I can't tell you any more than I already have. If you think that you have a disease, then yes, you should take them out. There are a lot of other diseases besides RTN. There's also white band disease, for instance. I'm not saying anything about what you have because I don't have the corals in front of me. All I can say (again) is that you should never purchase a coral (especially SPS) that you suspect is diseased.

[Ninong]

Remember the old saying about adding anything to your tank: If you don't know what's in it, don't put it in. That applies to all those magic potions that refuse to identify their ingredients. It applies to "reef-safe" cures, too. If you don't know exactly what it is and exactly how it is supposed to work, forget about it.

The same advice can be applied to "sick" animals. If you see a tang with HLLE, you know that it is a nutritional disease and you know how to cure it. You also know that it is not contagious. If you see a tang with marine ich (Cryptocaryon irritans), you know what that is, too, and you wouldn't even dream of putting it in your tank.

The same holds true for SPS. If you don't know what it is, don't put it in your tank. If you have a completely separate hospital tank and you want to experiment in there, fine. But don't go putting something into a tank with perhaps thousands of dollars worth of corals and run the risk that you are introducing a pathogen that will spread like wildfire. You can do a search on Reef Central and find quite a few stories of people who lost virtually everything, or at least all of their SPS, after putting an infected wild-collected SPS colony in their tank. Some were lucky and only lost some of their corals.

[fishgeeksrus]

<praying> Lord if you let me get by this one, I promise I will never buy another coral that has an noticable problem!!!