Duncan tissue recession on branches.

[Hypnotoad]

So I've got this Duncan colony that started as two heads in March of 2016. Now it's many heads. Here's my Clownfish hanging out in it:

Anyway, most Duncans I've seen-including this one for the first 2 years of its existence in my tank-have green flesh connecting the entire colony, but lately mine looks more and more like this:

The polyps are still healthy and have flesh extending down onto the skeleton, but there is also bare skeleton visible now, and it's covered with feather dusters and pineapple sponges.

Has anyone else had this happen? should I be concerned, or does this happen once the colony gets bigger and certain spots quit getting lights, like I've seen on acro colonies before? Maybe time to get to fragging? Anyway, interested to hear some thoughts.

 

[Chad Sepulvado]

How long has it been this way ?

 

[Hypnotoad]

How long has it been this way ?

Couldn't say exactly. I noticed it recently, but all sponge and duster growth makes me think it must have been a while. Up top where it gets light more reliably, the tissue seems to cover the skeleton more.

 

[Hypnotoad]

anyone else have thoughts?

 

[Abeal17]

It seems like it's a dense colony, and this is only happening to the sides of the colony, then I'd say it's cause the areas where the tissue has died/ recessed is because those areas there's little light.

 

[Hypnotoad]

It seems like it's a dense colony, and this is only happening to the sides of the colony, then I'd say it's cause the areas where the tissue has died/ recessed is because those areas there's little light.

This is kinda what I've been thinking. I always assumed that the contiguous flesh between heads meant that the colony was sharing nutrients or that the polyps were communicating in some way. Does that mean that these isolated lower heads are technically their own mini-colonies?

Anyone frag duncans before? The colony is super encrusted to the rock so the only practical way to frag would be bone cutters inside the tank. Anyone ever had success with that method?

 

[MTBake]

I've seen this on large colonies of duncan coral. I had a colony that was larger than a football in last tank. That colony had this happening on some areas that received less light and flow due to growth. The overall health of the colony was fantastic besides the receding between 'stalks', for lack of a better word.

 

[Hypnotoad]

Thanks guys. I'll keep an eye on things but I suspect it's fine. If anyone has anything to say about my fragging questions and quasi-philosophical, pseudo-scientific comments regarding what defines a colony and how they work, I'd love to hear some speculation.

Thanks again though.

 

[Abeal17]

Thanks guys. I'll keep an eye on things but I suspect it's fine. If anyone has anything to say about my fragging questions and quasi-philosophical, pseudo-scientific comments regarding what defines a colony and how they work, I'd love to hear some speculation.

Thanks again though.

I'm sure it's fine, I believe it's fairly common in acropora that the inner parts of the colony will recess or die because of the lack of flow and light in the inner parts of the colony. I would only worry if you see the heads/ polyps become stressed. You could frag parts of the colony off on the underside and edges, but I don't know if the tissue would grow back in the center. You could frag a branch off and see if the tissue regrows to the exposed area and forms another branch.