Acro brown pale patches

[Paulb89]

Hi all, I'm looking for some advice as to why some of my sps colonies have developed this pale brown patch and they don't seem to be getting any colour back.

They're receiving light and not shadowed in anyway, could it be a pest?

 

[DanyL]

This how STN looks like - a slow degradation of the tissue, until eventually the coral gives up and die.

It could be a pest, lack of light (which you say it receives enough but didn’t mention how much), lack of flow, or parameter issues.

I suggest starting with posting your parameters here and answer the flow and lighting question.

If those are fine - I would check for pests or possible coral nippers, could be a fish, a crab or something else as well.

 

[Paulb89]

This how STN looks like - a slow degradation of the tissue, until eventually the coral gives up and die.

It could be a pest, lack of light (which you say it receives enough but didn’t mention how much), lack of flow, or parameter issues.

I suggest starting with posting your parameters here and answer the flow and lighting question.

If those are fine - I would check for pests or possible coral nippers, could be a fish, a crab or something else as well.

They have been this way for a year now

Alk 7.5
Nitrate 10.0
Phosphate 0.05

Triton icp comes back clear

The tank is lit by orphek Atlantic icons, they recieve about 300 par, checked with apogee meter

I don't have any fish that are sps nippers

What pests can do this and what do they look like? I can't see anything with the naked eye

 

[Paulb89]

They have been this way for a year now

Alk 7.5
Nitrate 10.0
Phosphate 0.05

Triton icp comes back clear

The tank is lit by orphek Atlantic icons, they recieve about 300 par, checked with apogee meter

I don't have any fish that are sps nippers

What pests can do this and what do they look like? I can't see anything with the naked eye

The tank has ample flow, 40,000lph

 

[DanyL]

They have been this way for a year now

What about Calcium, Magnesium and PH?

The tank is lit by orphek Atlantic icons, they recieve about 300 par, checked with apogee meter

That should be enough for them, so it’s indeed not a lighting problem.

I don't have any fish that are sps nippers

You never know, and it’s hard to catch.
Even herbivores sometimes develop a taste for Acropora tissue.
But crabs are usually a more prominent problem.

What pests can do this and what do they look like? I can't see anything with the naked eye

See the small white speks on the first and third pictures? These could be white bugs, or just debris. Really hard to tell with the naked eye, but a closer look would definitely help identifying it.

There are also other kinds of bugs, and pests such as black and red bugs and AEFW.
Most do a good job hiding or making themselves invisible to the naked eye.

For AEFW for example, the easiest way to identify them is by using a small pump to blow them off an Acropora, directing it at different angles over the coral tissue and closely watching what flies away.

I also recommend look at the corals at night with a flashlight, pests sometimes reveal themselves only at night.

The tank has ample flow, 40,000lph

It doesn’t tell much.
A good flow for most acros is strong, indirect and random - one that comes from multiple sides and angles and blows off any mucus and detritus that may have accumulated or fallen on the tissue, even between the tightly packed branches.

 

[Paulb89]

What about Calcium, Magnesium and PH?


That should be enough for them, so it’s indeed not a lighting problem.


You never know, and it’s hard to catch.
Even herbivores sometimes develop a taste for Acropora tissue.
But crabs are usually a more prominent problem.


See the small white speks on the first and third pictures? These could be white bugs, or just debris. Really hard to tell with the naked eye, but a closer look would definitely help identifying it.

There are also other kinds of bugs, and pests such as black and red bugs and AEFW.
Most do a good job hiding or making themselves invisible to the naked eye.

For AEFW for example, the easiest way to identify them is by using a small pump to blow them off an Acropora, directing it at different angles over the coral tissue and closely watching what flies away.

I also recommend look at the corals at night with a flashlight, pests sometimes reveal themselves only at night.


It doesn’t tell much.
A good flow for most acros is strong, indirect and random - one that comes from multiple sides and angles and blows off any mucus and detritus that may have accumulated or fallen on the tissue, even between the tightly packed branches.

Calcium 450
Mag 1350
Ph 8.3

I've never seen any of my fish nipping at the flesh and my wife is home all day and hasn't seen anything either.

The flow is randomised, I have 2 gyres opposing each other on a different setting and another in each corners disrupting that flow so it's quite turbulent.

The brown patches aren't a loss of flesh, they're just brown flesh with no skeleton exposed, the white bits you see have always been there and they extend when food is broadcast, I assume they are feeding tentacles as they don't come off or move places.

 

[DanyL]

Calcium 450
Mag 1350
Ph 8.3

Params look correct.

I've never seen any of my fish nipping at the flesh and my wife is home all day and hasn't seen anything either.

Any crabs?
Could be a night nipper.

The flow is randomised, I have 2 gyres opposing each other on a different setting and another in each corners disrupting that flow so it's quite turbulent.

Could also be too much flow.
Are all acros affected or just these 3?
Any other coral issues, or is it just Acroporas?

The brown patches aren't a loss of flesh, they're just brown flesh with no skeleton exposed, the white bits you see have always been there and they extend when food is broadcast, I assume they are feeding tentacles as they don't come off or move places.

Yes, that’s exactly what STN looks like.
Brown/pale tissue with little to no polyp extension.

I’m hesitant to propose the use of antibiotics before exhausting all other possibilities, but it could also be a bacterial issue, an imbalanced biome can cause STN as well, though often times it isn’t the case.

I would closely monitor how this develops and keep looking for pests, if you don’t come up with any visible reasoning, I would take the colonies out and do cipro/ivermectin treatments, this should stop any local bacterial activity that might be the root problem you’re experiencing here.

 

[Paulb89]

Params look correct.


Any crabs?
Could be a night nipper.


Could also be too much flow.
Are all acros affected or just these 3?
Any other coral issues, or is it just Acroporas?


Yes, that’s exactly what STN looks like.
Brown/pale tissue with little to no polyp extension.

I’m hesitant to propose the use of antibiotics before exhausting all other possibilities, but it could also be a bacterial issue, an imbalanced biome can cause STN as well, though often times it isn’t the case.

I would closely monitor how this develops and keep looking for pests, if you don’t come up with any visible reasoning, I would take the colonies out and do cipro/ivermectin treatments, this should stop any local bacterial activity that might be the root problem you’re experiencing here.

No I haven't seen any crabs at all.

It's just these 3 and the shortcake is quite far from the other 2, all of these 3 are wild pieces, however no other acros are affected and no other coral issues.

The polyps on all 3 don't indicate too much flow

I apologise, I always thought STN exposed the skeleton underneath same as RTN but at a slower rate, these pieces have been like this for over a year and continue to grow.

I'll keep an eye out for pests but looking tonight I can't see anything with a torch.

 

[DanyL]

It's just these 3 and the shortcake is quite far from the other 2, all of these 3 are wild pieces, however no other acros are affected and no other coral issues.

Wild colonies can sometimes be harder to acclimate, and weaker health can open the path to local bacterial infections that will cause STN.

I apologise, I always thought STN exposed the skeleton underneath same as RTN but at a slower rate, these pieces have been like this for over a year and continue to grow.

STN can start and stop exposing skeleton in patches, but it can also stay in this intermediate state for a long time and even show some growth until it finally fails and dismantles the tissue from these areas.

Like I mentioned earlier - I'm hesitant to jump to antibiotics before exhausting all other options, but it could be the remedy needed here.

I also had some success saving colonies in this state by heavily fragging them, basically fully taking them apart into small pieces, some survived while most unfortunately faded away.

 

[Dburr1014]

Looks like cyano settled in to me.
Up your flow.

The tank has ample flow, 40,000lph

You may have ample flow but is it directed in the right places?