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Could this be RTN?


DaveMc

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Morning everyone,  have a question. Just a few days ago I completed my normal water change and parameter check as I normally do. Everything was looking good with corals. Today I noticed my birdnest looked a little different. Could this be RTN?

 

Any help would be appreciated. 

 

 

16353465002691357109438815605458.jpg

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Yep. Might be big trouble.

 

That's either a bird of paradise or neon green. Its too browned out to tell, and a brown birdsnest is a sick birdsnest.

 

Birdsnest corals are very, very fussy when it comes to phosphate levels being too low or erratic. They are more tolerant of nitrate.

 

The fact I can see growth nodes indicates you either just got it and your water params aren't compatible, or you've had it a bit and are having massive nutrient swings.

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2 hours ago, blasterman said:

Yep. Might be big trouble.

 

That's either a bird of paradise or neon green. Its too browned out to tell, and a brown birdsnest is a sick birdsnest.

 

Birdsnest corals are very, very fussy when it comes to phosphate levels being too low or erratic. They are more tolerant of nitrate.

 

The fact I can see growth nodes indicates you either just got it and your water params aren't compatible, or you've had it a bit and are having massive nutrient swings.

Thanks Blasterman for the information. Figured that may be what was the issue. I know my Nitrates normally stay at 10ppm after each water change. Unfortunately I don't have a phosphate test yet....still need to get one. Would it at least be worth a try and frag the other pieces off and try again? Or just count it as a loss?

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It could be coral bleaching  tissue necrosis due to stress. RTN and STN are caused by an infection due to a microscopic parasites. Bleaching is due to stress. SPS can recuperate after having bleached having some tissue necrosis due to stress (even after losing some of its tissue).

IMG_4073.thumb.JPG.f1154ffea9f3cae891ee7f7f730efcfd.JPG
For example, my birdnest that did bleach did have some tissue necrosis because of too much flow is slowly recuperating .

Edited by M. Tournesol
correction of the reefing-vocabulary
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That is not bleaching in the OPs picture. Its dead tissue. This is how birdsnests die. The fact it's brown is a dead hive away something is wonky with nutrients.

 

STN and RTN in SPS  are also most commonly caused by nutrient swings. Acropora are the worst offenders. 

 

If the tissue necrosis continues to creep up the base i would frag it ASAP.

 

Birdsnests are pushed as beginner SPS corals when they shouldn't be. They are hyper sensitive to phosphate swings and I've seen too many beginners with the same problem. Blue/green digitata or pocillopora can tolerate phosphate swings in young tanks much better along with purple stylos. Those are the best beginner SPS. 

 

The salifert phosphate kit is good on a budget with the Hannah being the standard. I use salifert because I'm cheap, but it tells me what I need to know. If you get the asalifert use 5ml of water as a test reference vs 10ml as the directions say. It will be easier to read and more sensitive. 

 

Attached is the dinner plate size birdsnest I just hauled out of my 20gal and gave to the local reef shop.

 

20211014_113445.thumb.jpg.894d9839f8cf3f3b47008d461429acf4.jpg

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3 hours ago, blasterman said:

That is not bleaching in the OPs picture. Its dead tissue. This is how birdsnests die. The fact it's brown is a dead hive away something is wonky with nutrients.

 

STN and RTN in SPS  are also most commonly caused by nutrient swings. Acropora are the worst offenders. 

 

If the tissue necrosis continues to creep up the base i would frag it ASAP.

 

Birdsnests are pushed as beginner SPS corals when they shouldn't be. They are hyper sensitive to phosphate swings and I've seen too many beginners with the same problem. Blue/green digitata or pocillopora can tolerate phosphate swings in young tanks much better along with purple stylos. Those are the best beginner SPS. 

 

The salifert phosphate kit is good on a budget with the Hannah being the standard. I use salifert because I'm cheap, but it tells me what I need to know. If you get the asalifert use 5ml of water as a test reference vs 10ml as the directions say. It will be easier to read and more sensitive. 

 

Attached is the dinner plate size birdsnest I just hauled out of my 20gal and gave to the local reef shop.

 

20211014_113445.thumb.jpg.894d9839f8cf3f3b47008d461429acf4.jpg

I see what you mean. To be honest, I was having issues with cyano and did add some phosban to my filtration. I really think thats when it started (color change). I have since removed it now that the cyano is gone. Sine then I have been doing 10-20% water changes weekly. My soft corals and my Blue Stylo are doing great...my stylo is starting to branch off more and very full of polyps.

 

This is my first attempt at SPS...always had softies of LPS. I did get the Birdnest for the same reason, was told they were easy for first time SPS corals. If I can't save this one I will look into the pocillipora and digitata next. I will get the salifert kit you suggested so I can start testing the phosphates. What is a good range for phosphate? I have always been the type that worried about nitrates, alk, mag and calc lol.

 

Your pic above of the birdnest it awesome. That if a beautiful specimen for sure. If I can't save this one, I will wait longer on another birdnest!

 

Appreciate the feedback Blasterman :)

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For young tanks you want to keep phosphate around .03...or just a trace on most wet kits. Phosphate is also what drives most nuisance algae so it can be a tricky balance and you dont want to go higher until the tank gets mature. Water changes hammer phosphate much worse than nitrate.

 

Don't get too obsessed with element levels. Calcium around 390- 450 and alk 8-9. 

 

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Hi @blasterman. I am still news to the Hobby (less than a year) and I would like to improve myself. From your previous posts, you seem to have given several elements that contradict what I have learned.

Can you enlighten me a little here?

8 hours ago, blasterman said:

That is not bleaching in the OPs picture. Its dead tissue. This is how birdsnests die.

I thought that the term RTN and STN was reserved for sickness( caused by bacterial strains, Brown Jelly Disease, or pathogenic bacteria) and for all tissue necrosis due to stress in a new tank. Is this photo an RTN/STN caused by sickness or is the term simply used more generally in the hobby to qualify all tissue necrosis?

 

5 hours ago, DaveMc said:

The fact it's brown is a dead hive away something is wonky with nutrients.

5 hours ago, DaveMc said:

The fact it's brown is a dead hive away something is wonky with nutrients.

I don't understand this reasoning. Shouldn't brown corals be caused by a lot of nutrients or/and a whiter light spectrum?
In nature, corals are generally brown. 

133181_seriatopora-hystrix-birdsnest-cor

In sunlit reefs (light tubes/windows skylight), the corals are also generally browner.

dsc_0032.jpg

 

Why would brown corals be a giveaway that something is wonky with nutrients?

 

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10 hours ago, blasterman said:

The salifert phosphate kit is good on a budget with the Hannah being the standard. I use salifert because I'm cheap, but it tells me what I need to know. If you get the asalifert use 5ml of water as a test reference vs 10ml as the directions say. It will be easier to read and more sensitive. 

I use the salifert phos test as well and never appear to get a reading above 0.03, and this is the first time I have heard of using half the amount of sample water for a more accurate reading. Do you halve the amount of reagents as well or leave as is?

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7 hours ago, DaveMc said:

I see what you mean. To be honest, I was having issues with cyano and did add some phosban to my filtration. I really think thats when it started (color change). I have since removed it now that the cyano is gone. Sine then I have been doing 10-20% water changes weekly. My soft corals and my Blue Stylo are doing great...my stylo is starting to branch off more and very full of polyps.

 

This is my first attempt at SPS...always had softies of LPS. I did get the Birdnest for the same reason, was told they were easy for first time SPS corals. If I can't save this one I will look into the pocillipora and digitata next. I will get the salifert kit you suggested so I can start testing the phosphates. What is a good range for phosphate? I have always been the type that worried about nitrates, alk, mag and calc lol.

 

Your pic above of the birdnest it awesome. That if a beautiful specimen for sure. If I can't save this one, I will wait longer on another birdnest!

 

Appreciate the feedback Blasterman 🙂

Cyano is typically a sign of too low-phosphates, similarly to that kinda tissue necrosis on the birds nest, chances are your phosphates just recently bottomed out and the corals that are looking healthy are resillient when it comes to low PO4. 

 

I'd remove the phosban because it's just throwing the balance off, I think you want to carefully and slowly increase phosphates, while keeping your nitrogen inputs balanced (like increasing feedings while adding amino acids, or just dosing some phosphates)

1 hour ago, M. Tournesol said:

Hi @blasterman. I am still news to the Hobby (less than a year) and I would like to improve myself. From your previous posts, you seem to have given several elements that contradict what I have learned.

Can you enlighten me a little here?

I thought that the term RTN and STN was reserved for sickness( caused by bacterial strains, Brown Jelly Disease, or pathogenic bacteria) and for all tissue necrosis due to stress in a new tank. Is this photo an RTN/STN caused by sickness or is the term simply used more generally in the hobby to qualify all tissue necrosis?

 

I don't understand this reasoning. Shouldn't brown corals be caused by a lot of nutrients or/and a whiter light spectrum?
In nature, corals are generally brown. 

133181_seriatopora-hystrix-birdsnest-cor

In sunlit reefs (light tubes/windows skylight), the corals are also generally browner.

dsc_0032.jpg

 

Why would brown corals be a giveaway that something is wonky with nutrients?

 

RTN and STN are just hobby terms for tissue necrosis, when you look at how tissue necrosis manifests there are many 'kinds' like follows:

 

  • stripping of flesh from the base, where it seems to be absorbed and show skeleton
  • stripping of flesh from the base where it flakes off in strands
  • rings around the base that slowly progress
  • sudden full tissue loss across branches / whole colony 
  • lesions in the middle of the colonies
  • bubbling that causes lesioons as above 
  • cancerous hyper/neoplastic growths at the tips that cause tissue to flake off after looking all blistered 
  • tissue receeding from the tip where it seems to be absorbed and show skeleton

 

All of the above someone would call 'RTN' or 'STN' and these terms give little to no explanation for the mechanisms causing them.

 

The brown coral colour you're asking about is usually not just related to phosphates (most people think phosphate and nitrate are nutrients, but so are potassium, iodine, nickel etc) and usually is related to the balance of phosphate : iodine in the water. Higher iodine in the presence of phosphate causes that rich golden brown colour, and low phosphate with low iodine causes the inverse. Eitehr phoshphate or iodine completely depleting from the water will cause types of necrosis I outlined above, usually the first or third bullet point. Nitrogen tends to cause the second, and the nitrate in relation to kH tends to cause the last bullet point.

see: https://www.faunamarin.de/en/knowledge-base/iodine/ and below from that site:

image.png.7af16b6628d1309ffb890f535589150a.png

 

The others are a little more complex and usually relate to overdoses and ionic balances

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21 hours ago, blasterman said:

For young tanks you want to keep phosphate around .03...or just a trace on most wet kits. Phosphate is also what drives most nuisance algae so it can be a tricky balance and you dont want to go higher until the tank gets mature. Water changes hammer phosphate much worse than nitrate.

 

Don't get too obsessed with element levels. Calcium around 390- 450 and alk 8-9. 

 

Thank you blasterman. I ordered the Salifert test so once it comes in will keep an eye on it. Woudl you recommend bi-weekly water changes compaired to weekly since it will hit the phosphates more than the nitrates?

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On 10/28/2021 at 5:32 AM, East1 said:

RTN and STN are just hobby terms for tissue necrosis, when you look at how tissue necrosis manifests there are many 'kinds' like follows:

 

  • stripping of flesh from the base, where it seems to be absorbed and show skeleton
  • stripping of flesh from the base where it flakes off in strands
  • rings around the base that slowly progress
  • sudden full tissue loss across branches / whole colony 
  • lesions in the middle of the colonies
  • bubbling that causes lesioons as above 
  • cancerous hyper/neoplastic growths at the tips that cause tissue to flake off after looking all blistered 
  • tissue receeding from the tip where it seems to be absorbed and show skeleton

 

All of the above someone would call 'RTN' or 'STN' and these terms give little to no explanation for the mechanisms causing them.

 

this very well-described, I personally experience most, if not all of the above, lol. 

 

there's also the matter of "rapid" vs "slow", R vs S, in RTN vs STN that no one seems to define.  I had RTN that's lost the whole colony lost tissue under 24 hours (that's where I might consider drawing the line for RTN).  and I've had multiple STNs that lingered on, and the coral either come back, or taken over by algae with the rest of the healthy portion just carried on.    

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7 hours ago, mitten_reef said:

this very well-described, I personally experience most, if not all of the above, lol. 

 

there's also the matter of "rapid" vs "slow", R vs S, in RTN vs STN that no one seems to define.  I had RTN that's lost the whole colony lost tissue under 24 hours (that's where I might consider drawing the line for RTN).  and I've had multiple STNs that lingered on, and the coral either come back, or taken over by algae with the rest of the healthy portion just carried on.    

I’ve had similar, this rapid vs slow assessment, the way I experienced it led me to categorise them as tissue necrosis based on a external biological factor (like a virus, bacteria consuming the tissue slowly) or an internal biological factor (when the coral dies from the inside out, because a lot of the rapid colony / branch deaths seem to come about from internal die off, almost like the mesoglea and digestive filaments die off and then the skin sloughs off in a matter of hours)  

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On 10/27/2021 at 10:55 AM, DaveMc said:

Just a few days ago I completed my normal water change and parameter check as I normally do.

Please mention the results of your water checks.  And tell us more about the tank, such as how old it it.  Also, anything else that might be interesting about it, such as it's flow and lighting, etc.

 

Were you doing the water change because the nutrient levels had gone too high or because the alk levels had gone too low?

 

On 10/27/2021 at 10:07 PM, DaveMc said:

To be honest, I was having issues with cyano and did add some phosban to my filtration.

Eek....without even having a phosphate test?

 

On 10/27/2021 at 10:07 PM, DaveMc said:

Sine then I have been doing 10-20% water changes weekly.

Sounds like you're doing them "just because".  If you aren't doing the water change for more or less one of the two reasons I mentioned above, you might actually be doing more harm than good with each one.

 

On 10/27/2021 at 10:07 PM, DaveMc said:

I did get the Birdnest for the same reason, was told they were easy for first time SPS corals.

"Easy" is a fairly meaningless term, unfortunately...very relative.  

 

Birdsnests are "easy" in so much as it's easy to tell if they are growing (because they grow FAST) and easy to tell when they are dying (as you see).  

 

Most corals are FAR less "emotive" in our eyes and can be in the process of growing or dying and you won't be able to tell...which is great and fine for the reef, but not helpful for a beginner reefer that's trying to know if they're "doing it right".

 

As has been mentioned, there are several other stony corals that are also "easy" but not quite as sensitive as the birdsnest.  Red or Green Montipora cap. is my all time favorite beginner stony coral.   Some M. digitata are great as well.  (Of course there are several others, including the Stylo you mentioned....these are just my fav's.)

 

On 10/28/2021 at 3:39 AM, M. Tournesol said:

I thought that the term RTN and STN was reserved

Those are made up terms that simply describe the hobbyist's experience....just literal descriptions of what happens.  

 

The tissue of a coral "suddenly" (or "rapidly" – your choice) dies.  (And we don't usually know why....so we need to make up a term to describe what happened.)

 

RTN can happen for any reason that is sufficient to kill your coral.  These things can include anything from a flow change to simple over-handling during placement to chemistry (including dissolved nutrients) swings....and anything else you can think of too.

 

So, unfortunately, the condition being "RTN/STN" doesn't really tell you anything more than what is already obvious.

 

On 10/27/2021 at 10:07 PM, DaveMc said:

What is a good range for phosphate? I have always been the type that worried about nitrates, alk, mag and calc lol.

Remember that these things are nutrients, not toxins or anything bad.  

 

Your job is to make sure these nutrients don't run out.  It's that simple.

 

You probably add tons of phosphorous and nitrogen when you feed the tank.

 

In most tanks, especially new tanks, a good percentage of that ends up as dissolved nitrate and dissolved phosphates.

 

Everything in a reef that depends on dissolved nutrients, will be affected to their detriment if there are spikes (high or low in some cases) in these parameters.  Balance is the key.

 

Here is a handy analogy (if the function of a car engine isn't totally foreign to you) where photosynthesis is concerned:  

  • Photosynthesis is like a car engine
  • Nitrogen is like gasoline.  
  • Phosphate is like oil.  
  • An engine (ie photosynthesis) won't run correctly if either one is missing.  
  • Without gas, combustion stops.  
  • Without oil, the whole engine will melt or even explode.

You can see that it's much less critical to run out of gas, where you just have to get more gas, than to run out of oil, in which case the engine is permanently ruined.

 

Here's a journal article that speaks to this, which includes pictures at three magnification levels...one macro and two microscopic shots....of what that engine meltdown looks like when it happens in a coral:   Phosphate deficiency promotes coral bleaching and is reflected by the ultrastructure of symbiotic dinoflagellates

 

1-s2-0-s0025326x17301601-gr1.jpg

(H=high; L=low; P=phosphate; N=nitrate)

 

Every one of those white/see-through gaps in the center and left-hand images is a melted down or exploded engine from our analogy.

 

You can see on the left-hand image what those conditions look like to our eyeballs.

Edited by mcarroll
over-handling, not overhauling
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On 10/28/2021 at 3:39 AM, M. Tournesol said:

I don't understand this reasoning. Shouldn't brown corals be caused by a lot of nutrients or/and a whiter light spectrum?
In nature, corals are generally brown. 

A bit of misnomer....the brown isn't caused by nutrients.  It's caused by increases in dinoflagellate population density.

 

What causes an increase in dino density?

 

Generally that's caused by nitrogen spikes.  But there are usually other factors at work too from whatever conditions caused the spike.

 

Spikes (or dips) in other nutrients aren't very strongly associated with dino cell division...so not really strongly associated with browning per se.

 

Also, single-nutrient spikes aren't common in an aquarium, (but single-nutrient spikes seem to be what's considered in most journal articles).

 

In a healthy aquarium, nutrient levels across the board tend to be high.  This is fine for corals, maybe even preferable, as long as it is stable.

 

In the wild, those conditions are rarely stable, and corals don't generally prosper in those conditions as a result.....macro algae or something else will assume dominance in those cases.

 

In a tank, where we all tend to maintain a strict set of nutrient input (ie feeding our fish) it's very possible to have stable, high nutrient levels.

 

The Birch Aquarium at the Scripps Institute is reputed to maintain conditions like this in their coral breeding system....they've posted several times about it.

 

The only corals I've seen in nature that compare with the pastel colors we see so often in highly-polished coral photos are corals that are in the process of bleaching – not healthy corals.

 

Healthy reefs are often yellow/brown.  Bright colors are definitely not the norm, but are more normal than pastels.  Non-corals are often brighter than corals.

 

This is a great thread for setting your expectations:

 

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On 10/28/2021 at 9:47 PM, DaveMc said:

I ordered the Salifert test so once it comes in will keep an eye on it. Woudl you recommend bi-weekly water changes compaired to weekly since it will hit the phosphates more than the nitrates?

I would forget the schedule and do them as-needed....mostly based on alkalinity tests/to prevent alk from dipping toward <7dKH.  Or, make them very small....like 5%.

 

But I would probably not do a water change if phosphates were too low to sustain it without dipping toward ≤0.03 ppm.

 

Some folks in unusual circumstances have dosed their water change water with enough phosphate so they could do the water change without reducing the existing level of po4 in the tank.  Easy to do, but shouldn't be necessary in most cases....just don't do a water change.  In that case, dose something to raise alkalinity instead of using the water change to do it.

 

 

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So sorry everyone for the slow replies here, work has been a bear here because of holidays coming up. I promise I will respond tomorrow as soon as I can. I truly appreciate all the replies and will get back to each one. 😃

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