What could be the cause of coral bleaching from the center out

[Jan]

I've dipped and dipped and I don't see anything; no flatworms, no red bugs, no crabs, no nothing other than detritus. What could be the cause of coral bleaching from the center base out? Could high phosphates cause bleaching? Haven't check phosphates yet.

[davelin315]

SPS? Lack of flow, detritus settling in the branches, or lack of lighting can also be a cause of problems for it, but there are also a myriad of other things that could be causing it, too. Is it RTNing?

[ctenophore]

If detritus settles in the branches, that can cause it. Either as a physical irritant or bacterial infection. Also some types of algae will grow in the same manner, causing slow necrosis.

[Jan]

Hmmm, I don't think so. RTN is usually fast, isn't it? This has been happening for about 2 weeks now. The only thing for sure is that it's happening from the center base out. Like what you might see with flatworms, but I can't find any flatworms.

 

SPS? Lack of flow, detritus settling in the branches, or lack of lighting can also be a cause of problems for it, but there are also a myriad of other things that could be causing it, too. Is it RTNing?

 

This is definately a slow necrosis. I'll point a lower flow powerhead at it. I was afraid a high flow might cause the polyps to retract and cause more necrosis. It's just one coral. A large colony of a bushy acropora. My understanding is that they are a difficult coral.

 

If detritus settles in the branches, that can cause it. Either as a physical irritant or bacterial infection. Also some types of algae will grow in the same manner, causing slow necrosis.

[ctenophore]

This is definately a slow necrosis. I'll point a lower flow powerhead at it. I was afraid a high flow might cause the polyps to retract and cause more necrosis. It's just one coral. A large colony of a bushy acropora. My understanding is that they are a difficult coral.

Is it a wild or large mariculture colony? It's probably just not getting enough flow inside it. Try cutting out some center branches to make it more bowl-shaped, that should help it breathe in the middle. Also point a powerhead underneath it so water flows up through the branches. This will help keep detritus from compacting down into the branches. If the tissue has receded too far, you may just want to cut the branches off and glue them down in various places.

[reefhunter]

my huge blue tort colony is dead in the middle/base from lack of flow and detritus. It is VERY healthy.

 

the base of my green slimer died (when it was in borets tank and he was out of the country). It is thriving.

 

I think certain SPS get so big that detritus and low flow in the center of the colony cause this problem. Also, branching corals block the light to the base which may also contribute.

 

Is it spreading still or has it stopped once the recession it hit tissue in good flow?

[Coral Hind]

I too think that lack of flow is normally a cause for tissue death in the middle as was mentioned.

 

The dips can also stress the coral and make the issue STN more.

Is the light being blocked as the coral grows. How old are the lights?

Are there any acro crabs living in it?

[Jan]

It was still spreading as of this post. I cut it back a bit and placed a power head facing the center. I hope it works.

 

my huge blue tort colony is dead in the middle/base from lack of flow and detritus. It is VERY healthy.

 

the base of my green slimer died (when it was in borets tank and he was out of the country). It is thriving.

 

I think certain SPS get so big that detritus and low flow in the center of the colony cause this problem. Also, branching corals block the light to the base which may also contribute.

 

Is it spreading still or has it stopped once the recession it hit tissue in good flow?

[Jan]

Thanks everyone. I've cut it back a bit and I have higher flow on it. I hope it works. I'll keep you posted.