Update 2-25-25
It’s been a while since my last update, and unfortunately not a happy one (though hopefully useful for others).
~9-10 months ago, I started having another round of torches dying off. It was identical to the last occurrence, and was a repeat of the same issue that’s plagued me for about four years now:
- A torch colony—or just one head, or several heads on the same colony—would inflate less
- The flesh would start to recede from the bottom up
- The flesh would start to ‘peel’ off from the torch
- The flesh would slough off, and the torch would die; anywhere from several days to several weeks following the initial symptoms
We’d primarily kept torches in the past, or very hardy goniopora. However, this issue (or something like it) seemingly began affecting almost every other piece in our tank: we lost hammers, frogspawn, gonis, SPS, and acropora. All in the same frustrating manner of, “Random pieces choosing to die at varying rates of speed, with no rhyme or reason as to why,” which has let us with a grand total of two of our original 12+ torches. This has been beyond frustrating, and has significantly impacted my enjoyment of the hobby, but I am also pretty good at turning 'being pissed off' into 'figuring something out', so I'm not giving up yet.
(
You can skip ahead at this point, since I’m just doing a comprehensive rundown of what I’ve tried for those trying to troubleshoot in the future)
I figured there were several possibilities: it could be chemistry/nutrient-related. It could be a fish biting/harming the coral. It could be parasites. It could be bacterial. Going through all of these:
- Chemistry: I test four times a day with my Trident; similarly, I test nutrients every week or two with Hanna checkers. I won’t dig through my logs for exact numbers, but nothing was consistently out of line in a way that made me think chemistry was an issue. ICP tests confirmed this, with the only consistent issue being lower-than-ideal iodine.
- Fish issues (or ‘fisshues’): One immediate possibility was our aiptasia-eating filefish (I’ve had issues with one in the past nipping at acans and fleshy corals). However, after observing it for long periods of time, I’d lean towards fish not being the cause of my issues (especially since I feed fairly heavily).
- Parasites: Everything added to my display tank has gone through a full quarantine including visual inspection and dips in CoralRx and/or potassium chloride.
- Flatworms were an initial obvious concern, but 1) all coral going into QT is visually inspected, 2) they’re dipped multiple times every few days if evidence is found, 3) the QT was treated with Flatworm eXit several times, and 4) I have a pearly wrasse in the DT for biological control.
- I initially thought euphyllia-eating white bugs may be the culprit, given I saw some on my dying reverse tiger torch. However, treating both the main display and QT tank with Interceptor had no effect on the recurrence of this issue.
- Bacterial: See below
Aquabiomics & chatting with Rich Ross
The only thing I could potentially think of at the time was something biological. It made sense: the issues has followed me through four separate tanks now. It waxes and wanes (consistent with shifting diversity and general system health). The coral dying was not brown jelly disease, but that didn’t necessarily rule out bacteria or something else. So I did both eukaryotic and bacteria Aquabiomics tests to try and get an answer.
While I’m generally skeptical about drawing conclusions from these tests—specifically because there’s a big gulf between “having X proportion of Y bacteria in your tank” and “that observation being the cause of the underlying dysfunction in your tank”—I did get one very interesting result.
View attachment 66510
Pictured: One very interesting result
Two things spring to mind. The first is that I have a ~15x higher incidence of this bacteria than the average tank they test (and 5x higher than the ‘high’ end of the typical range). The second is that phrase SCTLD, which I hadn’t heard of before. So I did a bit of digging.
It turns out that SCTLD stands for
Stony Coral Tissue Loss Disease. The symptoms, interestingly enough, seem highly consistent with what I’ve experienced. Doing more digging, research articles have shown it can be transferred via infected coral tissue, water, and sediment (which is consistent with this issue following me through several tanks). Adding one additional piece of evidence, the only soft coral in our tank—a magic carpet mushroom—is thriving and happy. The down side, however, is that there’s no clear consensus if this issue is bacterial, viral, eukaryotic, or ‘some combination of all of the above.’
Additionally,
@Thales was kind enough to discuss my issues with me after the frag swap this past weekend, and agreed that my issue sounded like it was either bacterial or confounded by bacteria. After discussing his bout with a previous, superficially similar issue, he brought up that oxolinic acid had seemingly resolved his issue (as well as admitting that, “Well, you’re basically in uncharted territory.”)
So, still no a guarantee, but: it’s a starting point.
Making a plan
After all of the above, I’m opting to try a treatment strategy with oxolinic acid with the following rationale:
- My issue is likely biological, given it’s followed me from tank to tank and does not appear to be either chemistry-, fish-, or parasite-based.
- The strongest lead at the moment is an overabundance of bacteria associated with SCTLD, which is consistent with the issues I’m experiencing
- @Thales had a prior issue superficially similar to mine, which cleared up after treatment with an antibiotic (oxolinic acid)
- Oxolinic acid is relatively reef-safe and is less likely to cause any nasty side effects
Additionally, because I’m a bench scientist at heart and because any data contributing to understanding the underlying issues of SCTLD is welcome, I’m planning on doing an Aquabiomics test immediately after following Rich’s protocol for treating with oxolinic acid.
Finally, I’m going to be experimenting with another veterinary-adjacent company—MiDog DNA—that claims to do marine DNA testing. I’m getting more information from them right now, but looking into what they have publicly available it seems like they run on the same ‘backbone’ that Aquabiomics does (16S ribosomal RNA sequencing). Best of all, it seems they offer a turnaround time of 2–5 days (which would let me immediately jump to another treatment if this one fails), rather than Aquabiomics’ rather…let’s say
lengthy turnaround time.
