A question that I struggle with, and I'm sure others do as well...

[jassermd]

So here's an issue that I'm sure we all deal with... We all agree that tank stability, flow and lighting are critical for coral health and growth. And fluctuations or swings of said parameters create challenges.
That's not the issue here... Let's say said tank is >1 yr old, all parameters are within range (I'd be glad to list hypothetical parameters, but for the sake of this discussion, they are what we all expect to be ideal) and never fluctuate (as would be expected for a fully mature tank that's well maintained)
Let's just say that there are 15-20 frags and colonies of torches and frogspawns which are fully extended and happy.
Here's the dilemma: Why then, after 2-3 weeks of being fully open and happy, does one torch (or frogspawn for that matter) up and die? Never has been moved or messed with since the day it goes into the tank. And, as mentioned previously, NOTHING changed regarding tank parameters, flow or lighting. And, all the other inhabitants in the tank are doing great. Same goes for display... This is something I've seen folks deal with on these threads, and although in most cases there is an underlying reason, in some there isn't.

The question I continually as myself: Why do some corals (in particular euphyllia) up and die for no reason after about 2-3 weeks of looking great, when NOTHING has changed (That includes all tank parameters, flow and lighting). No rhyme or reason... And dipping doesn't demonstrate any critters or otherwise. They just up and die.
Yeah, some will say BJD, which IMO, is more of a effect of something rather than being the cause. I don't buy it... What I'm trying to figure out is why this happens and is it something we can impact, or is it just a bad specimen that once settled says "the trip was nice, thanks for the rest, I'm out!"
As a physician, I'm plagued by the need to find an answer... hence the post. Would love to get others input and thoughts on this.

 

[Sierra_Bravo]

Whoever is the first to solve the mystery of why corals suddenly decide to die for no apparent reason will be hailed as the founder of the next new modern age of reefing.

I'm blessed that after nearly four years of keeping a reef tank I feel reasonably confident that most anything I put in the tank will survive. Having said that, one of my oldest colonies decided to STN out of the blue just recently. I have no clue why.

I expect that you'll get a lot of guesses, conjectures, and theories in response to your question, but no definitive answer. Keep at it, don't let it get you down, and accept that there will be some losses on the way in your journey.

 

[Dbichler]

I think that a lot of it has to do with how many times a frag has been fragged. Sure some make it and some don’t. Other situation I can think of is just how long is the life expectancy of any coral some say infinite. Is one temperature really good for corals or like nature some fluctuations happen. I’m no expert but just some of my thoughts.

 

[Gtinnel]

When that happens you will likely never know what caused it. The best guess I could give is that there are many compounds in our tank that we don't test for (unless you regularly send off samples for testing). It could be that certain corals are more susceptible to something in our tank that we don't even know is in there.

 

[PeterC99]

I believe things are constantly changing in our aquariums. Lighting, flow, and alk/calc demands change as corals grow. Only takes the slightest of changes to aggravate some corals.

Everyone gets upset when they lose a coral but it's truly remarkable that we can keep them in our artificial environments.

 

[Dkmoo]

these are the factors

1) "stability" in the sense you are describing, is only the tip of the iceberg. there is a lot more that's not measurable that could be variables. Just because all of your param, lighting, flow has been the same, doesn't mean that EVERYTHING that the coral experiences are the same. Their internal biology is a lot more complicated
2) just because a coral "appear" happy, doesn't mean they really are. some negative factors take months to manifest themselves. one example - corals that grew in relatively low pH environments can tolerate and even grow/split while maintaining the "healthy" appearance. however, over long period of time, it becomes evident that their bone is very brittle, and that their internal biology has maintained a homeostatis that was hanging on by a thread, that at some point, a slight variation on anything could be the last straw that broke the camel's back. Since a lot of the variables we cannot measure, to us, the appearance is "this coral has been healhty and happy for x months then suddenly died"
3) the measurable params is only the "left over" of what has not been consumed - it does not indicate what biological processes consumed them - some are visible - some are not. IE, a stable 1 ppm NO3 for a whole year could be the result of gha exposions, effective refugium, dinos, or cyano. All will take up no3 and give you the 1ppm per the test kit. but this doesn't mean tank biology has been stable. some of the differences we can tell - a gha explosion tank will look very different from a dino tank, however, the biological processes that's invisible will be much harder to distinguish, so that "a whole year of 1ppm no3" doesn't necessarily mean stable tank.

 

[schuby]

As was just stated, things are constantly changing in out tanks. We are deluding ourselves if we think anything inside our tanks is "constant and unchanging". Some people run their nutrients at the razor's-edge of low. I consider them the most likely to have sudden issues.

Even if we have automated dosing, feeding, and AWC, it is impossible for our tanks to be the same one day to the next or even one hour to the next. We manage our tanks but we can never absolutely control them to the nth degree.

 

[WVNed]

So here's an issue that I'm sure we all deal with... We all agree that tank stability, flow and lighting are critical for coral health and growth. And fluctuations or swings of said parameters create challenges.
That's not the issue here... Let's say said tank is >1 yr old, all parameters are within range (I'd be glad to list hypothetical parameters, but for the sake of this discussion, they are what we all expect to be ideal) and never fluctuate (as would be expected for a fully mature tank that's well maintained)
Let's just say that there are 15-20 frags and colonies of torches and frogspawns which are fully extended and happy.
Here's the dilemma: Why then, after 2-3 weeks of being fully open and happy, does one torch (or frogspawn for that matter) up and die? Never has been moved or messed with since the day it goes into the tank. And, as mentioned previously, NOTHING changed regarding tank parameters, flow or lighting. And, all the other inhabitants in the tank are doing great. Same goes for display... This is something I've seen folks deal with on these threads, and although in most cases there is an underlying reason, in some there isn't.

The question I continually as myself: Why do some corals (in particular euphyllia) up and die for no reason after about 2-3 weeks of looking great, when NOTHING has changed (That includes all tank parameters, flow and lighting). No rhyme or reason... And dipping doesn't demonstrate any critters or otherwise. They just up and die.
Yeah, some will say BJD, which IMO, is more of a effect of something rather than being the cause. I don't buy it... What I'm trying to figure out is why this happens and is it something we can impact, or is it just a bad specimen that once settled says "the trip was nice, thanks for the rest, I'm out!"
As a physician, I'm plagued by the need to find an answer... hence the post. Would love to get others input and thoughts on this.

Your question is curious but holds an unproven assumption.

Lets say you visit a friend and find him dead in his living room in the chair. Would you assume he died because something in the living room caused his demise like a pit viper in the chair or an undetected disease process did it like a clogged artery.

Do we know what the equivalent of snakebite looks like on a coral or the clogged artery for that matter.
There are probably few people in the world that can give a coral a health exam. Yes, sometimes that something is wrong is obvious but I am sure there are many conditions we don't notice. They do regularly change size, shape and color quite easily. Most of the time we cant even diagnose what causes those changes. Most of the time those changes aren't quickly fatal.

I am certain there is a reason they die, most certainly for the same reasons all things die, infection, starvation, perhaps age, poisoning, inappropriate environment, a long list.

The chances are slim to none that most of us hobbyists could detect those conditions in a timely manner and take appropriate steps to correct them. Especially the ones that don't cause a marked change in appearance to the untrained eye.

Sorry if that is an answer that doesn't satisfy you.

 

[jassermd]

You guys are great! It's a philosophical question that I struggle with... we've all lost corals that was due to our own negligence (or naivete), but those that were doing great and then up and die, continue to boggle my mind.

I agree, there are many compounds and other things that change at a microscopic level that we can't see or measure in the hobby. The explanation regarding skeletal growth and acclimation to a new environment is insightful. At the cellular level, minute changes can eventually create a detrimental outcome (i.e. cancer). Who's to say that one coral doesn't have a DNA mutation or has what later we call BJD, but is really more of a cellular issue. We really don't know the age, or longevity of the corals given our environments.
Oceans have perfected the process over the millions of years and it's fascinating that we can replicate it enough to have these amazing creatures live in our living rooms.
I struggle with it because I see it as my duty to do what I can to ensure their survival, not unlike my real job. Hence why I'm trying see what others think...

 

[Dkmoo]

You probably have better access to more medical/lab grade stuff that us mere mortals too... should give you an edge up.

Even something as simple as access to a microscope to confirm dino outbreaks already will increase your chances of long term success

 

[blasterman]

Euyphillia are one of those corals heavily harvested from the wild. In fact I think its the largest imported coral.

Wild caught corals have a significantly higher mortality rate in captive tanks.

 

[Weasel1960]

Great question. I don’t have a build yet but as I plan mine I was amazed how aggressive these creatures (fish, corals, etc.) can be towards one another. Maybe that sudden death is due to a battle that was lost with no witnesses?

It is somewhat challenging to plan a peaceful seahorse tank and not get caught by a sleepy aggressor.

 

[jassermd]

Totally agree! And the question is why?
And this isn't unique to just coral... in medicine, we encounter cases where there is no answer or error. In those instances, we are able to present the findings, collaborate with other docs, and try to figure out what really happened, if we can.
That's what I'm after... a discussion about what happens. I agree with the point that the variables we don't know and can't control are the ones that are likely causing more coral demise than we care to admit.
Saying that Ca is low, Mg is high, flow or lighting is too low/high is like walking into a patient room and seeing the monitor but not actually looking for the answer as to why they are dying. Yes, someone can have a low oxygenation, but it's the undiagnosed lung cancer that caused the issue. You can fix the O2 problem, but the real issue hasn't been addressed.
A conundrum...

 

[tehmadreefer]

There is much more to a successful reef tank then phos, nitrate, mag, cal and alk. You can have “perfect” numbers and stability and still can’t keep corals. Trace elements, bacteria, planktons and numerous micro organisms play a huge role.

That’s why you see so many failed sterile tanks these days with issue after issue after issue. They literally have zero biodiversity.

 

[Wick3d_1]

I think these lifeforms live on a razor edge regardless of location. Even in the ocean, they are thriving till they aren't. Whole reefs decimated without a clear answer. Yes, we have some clue but not always. When we put them in a tank, we don't think about that part. We know we are doing literally everything right as far as our collective knowledge. But there's so many, many unknowns with this hobby just like in our oceans. We know more about space and how it works than we do lifeforms in our oceans. It's frustrating and mind boggling.

 

[jassermd]

Extremely insightful! Interesting you post this exact point as I’m reading the article in Coral Mag on the microbiome and the importance this plays in the natural and captive reefs. My sense is that this plays a critical role in success and longevity of corals. Whose to stay that a specific bacteria/algae that is critical to the life of a specific coral doesn’t exist in one persons tank but does in another’s… and moving it from one to another is what causes the demise.
It’s fascinating and humbling at the same time.

 

[Wick3d_1]

I think our oceans will remain the one thing science never truly has an answer for. We have more definite answers about the stars in our sky than we ever will about the water at our feet. But we do the best we can and continue to learn.

 

[Scorpius]

Bacteria. A stressed organism is less likely to fight off the bad guys than a healthy and happy organism.

 

[Goaway]

Corals are a living animal. Like humans, we have a ton of things that just kill us. How are we to know what illness other than brown jelly takes place? We know mushroom corals get tumors just from led lights. Dying corals got sick somehow. The cause? Probably an injury that weakened the coral. Even if the wound healed. Who knows whats going on in the flesh?

 

[Timfish]

So here's an issue that I'm sure we all deal with... We all agree that tank stability, flow and lighting are critical for coral health and growth. And fluctuations or swings of said parameters create challenges.
That's not the issue here... Let's say said tank is >1 yr old, all parameters are within range (I'd be glad to list hypothetical parameters, but for the sake of this discussion, they are what we all expect to be ideal) and never fluctuate (as would be expected for a fully mature tank that's well maintained)
Let's just say that there are 15-20 frags and colonies of torches and frogspawns which are fully extended and happy.
Here's the dilemma: Why then, after 2-3 weeks of being fully open and happy, does one torch (or frogspawn for that matter) up and die? Never has been moved or messed with since the day it goes into the tank. And, as mentioned previously, NOTHING changed regarding tank parameters, flow or lighting. And, all the other inhabitants in the tank are doing great. Same goes for display... This is something I've seen folks deal with on these threads, and although in most cases there is an underlying reason, in some there isn't.

The question I continually as myself: Why do some corals (in particular euphyllia) up and die for no reason after about 2-3 weeks of looking great, when NOTHING has changed (That includes all tank parameters, flow and lighting). No rhyme or reason... And dipping doesn't demonstrate any critters or otherwise. They just up and die.
Yeah, some will say BJD, which IMO, is more of a effect of something rather than being the cause. I don't buy it... What I'm trying to figure out is why this happens and is it something we can impact, or is it just a bad specimen that once settled says "the trip was nice, thanks for the rest, I'm out!"
As a physician, I'm plagued by the need to find an answer... hence the post. Would love to get others input and thoughts on this.

Maybe our definition of "stability" is wrong or at least very inadequate :/. As I see it the typical assumptions about stability don't take into account any of the following:

From the research I've read the microbial processes in any reef ecosystem are likely in constant flux.

The different fluorescing and chromo proteins corals make are to cope with less than ideal environmental conditions (1) (2) (3) (4) (5). (colorful is not necessarily healthy.)

The different clades of simbodinium simbionts require different conditions and corals usually host more than one clade. Environmental changes (like differences between tanks) have the potential of changing the clade numbers and altering the photobiology (1)

Corals have "decadal" memory and the same two specimens of the same species/genotype or even in different parts of the same colony may react differently to the same conditions (1) (2).

Corals are influencing the bacteria in the water around them (1).

Each coral species has it's own unique microbiome (see Rohwer's "Coral Reefs in the Microbial Seas") which also includes components essential for it's immunity.

Immunity within a species varies significantly at the genotype level (1)

"Healthy" looking corals may not be. (1) (2) An excerpt from this paper -
"Critical to coral disease transmission – or resistance – is the coral's surface mucus layer,
which is produced in part by the coral's endosymbionts [12]. The mucus layer hosts a complex
microbial community, referred to hereafter as the surface microbial community (SMC). Because
the mucus environment is rich in nutrients, microbial population densities there are orders of
magnitude higher than in the surrounding water column [20]. Most established and emerging
pathogens are endemic to the ecosystem and typically present at low numbers in the SMC.
When stressed, the SMC can switch rapidly from a community associated with healthy corals to
diseased corals. In field studies during the 2005 summer bleaching event, Ritchie [28] observed
that "visitor" bacteria (bacterial groups otherwise not dominant) became the predominant
species in mucus collected from apparently healthy Acropora palmata."




(edited to add a 2nd link on "healthy" coral with apparently unhealthy microbiome)