Interesting experience with RTN...

[untamed]

I have two tanks at the moment...the 400 (new) and the 30 (4+ years old).

That's the background.

Jason...I killed your stag frag. It RTN'd in the 400 two days ago. In an attempt to save it, I trimmed the last healthy bit off and dropped the healthy bit into my 30 gallon.

That small bit also died...then today, two acros near the stag bit have RTN'd in the 30. The 30 gallon shares only 1 thing with the 400 (RO water comes from the same source). I use different salt brands...30 is kalk based, 400 is reactor based...they are completely isolated from each other.

It would seem that I transferred some sort of coral disease from the 400 into my 30 causing the immediate death of two acros. There are two more acros in the 30 that I want to save...so I fragged/dipped the remaining live corals in the 30 and distributed the frags in various spots in the 400. (distribute the genetic material, so to speak)

I have no idea what caused the original death of Jason's frag in the 400. It was fine for 3 weeks or so. I made a number of system tweaks that I thought caused the death at first...but if it was a system tweak, then how does it transfer to another tank?

I've been doing this for many years now and these are the first corals I've ever lost to RTN...and I'm not really sure what happened.

[Snappy]

IME the biggest causes of Rapid Tissue Necrosis are heat, nitrates/phosphates, low ca/alk. Poor lighting and flow can cause STN but that is a much slower death. Sometimes RTN just happens and there seems to be no logical reason.:neutral:

[fortheloveofcrabs]

Ditto. This hobby sucks. Sorry to hear about your corals... :(

[michika]

I agree with Greg/Snappy on the potential reasons, and I'm really sorry to hear this happened. Temperature can also be a factor, but from what you've mentioned isn't the trigger in this case. I would also venture to add too much direct flow to the list, but its less of RTN and more of literally blowing the flesh off kind of thing.

[untamed]

The 400 has all kinds of "new tank" issues, so I wasn't completely surprised that something went wrong...I immediately suspected any number of the things you've mentioned, but the 30 has been running flawlessly for years. There was no change in procedures, or any event beyond the introduction of the bit of coral.

I should have dipped that coral bit before I put it into the 30.....there's the lesson learned right there.

Since I was able to transfer the problem to a completely different and isolated tank, the cause must have been biological/microbial/viral...not environmental.

[Snappy]

Just a thought.
What type of corals do you have in your 30? Frags don't do well in a chemical warfare zone so in my opinion unless you run carbon to absorb the toxins out of the system they often won't make it. 30 gal is pretty small so there is a lot less "wiggle room" for error, especially sps.

[Reefer Rob]

I read somewhere that when one coral RTNs, it can trigger RTN in other corals in the tank, causing a chain reaction of sorts. Of course this all happens for not apparent reason :neutral:

[danny zubot]

I agree with the statment It would seem that I transferred some sort of coral disease

Though I'm not sure disease would be the term I'd use to describe it, maybe stress toxins? Who knows what kind of nasties a coral emits when it's under stress, but thats probably what caused this mess IMO. Terrible luck.

[Delphinus]

I actually think that RTN can also be called by protozoan, fungal, algal and bacterial causes.

It's sort of a double-whammy. Either conditions can be such that it will trigger RTN and STN quite easily, in which case, if one coral gets it, so too could a lot of others.

But also, because of the fact it could be protozoan, bacterial, fungal, algal, etc. -- once one host is "depleted" they look for another host and wham - again the chain reaction (even if conditions aren't "right" for promoting RTN).

Either way, RTN tends to be bad news.

I've been battling RTN and STN in my tank ever since I moved (THREE YEARS AGO). It started about 6 months after I moved. I think that I correct the cause, things are fine for a bit, then I'll have another mass loss event. You don't want to know how much money in frags I have lost in 3 years. It's now at the point where I am really uncertain about continuing in the hobby. Things are in a "holding pattern". I still have an empty 280g ready to be set up, that I've been working on, on and off for a while now, .. but .. when I look at my other tanks and see the list of problems that need to be solved, I get badly demotivated. A 280g with any of the same sorts of problems is going to be a nightmare of uncomparable magnitude. If I proceed, it has to be from ground zero. Problem is, I love my fish, they're pets, so I keep at it for their sake. But corals? Meh - I've been burned so badly on this now I honestly can't say that I care for corals other than being able to look at the pretty colours once in a while when they're not trying to have a massive death event. :(

Anyhow, ... sorry to rain on your thread. Hopefully your RTN is an isolated issue and not anything like mine.

[untamed]

I read somewhere that when one coral RTNs, it can trigger RTN in other corals in the tank, causing a chain reaction of sorts. Of course this all happens for not apparent reason :neutral:

I'm guessing that this is what happened. There's no reason to suspect that there was anything unusual going on in the 30. That tank was stable and hadn't changed (except for corals getting bigger) for a year or so. I add one tiny RTN survivor and...bang...two corals in the immediate proximity to the piece RTN.

[crystalz]

I wonder if the problem is due to the fact that both systems are so different... Different salts, calcium additive methods, etc. Big change from one to another?... Just a thought with it being a new tank.

[untamed]

I wonder if the problem is due to the fact that both systems are so different... Different salts, calcium additive methods, etc. Big change from one to another?... Just a thought with it being a new tank.

No way...not when the small tank has been established, happy and stable for years. Three coral have now all died in the small tank that had been growing perfectly well there for years. All within 48 hours of my trying to "rescue" that small piece.