Assistance required: Tabling acropora radial corralites turning white/dying

[Lapras]

Hi all,

Well, I have a larger sized tabling acro, and it seems within the last weeks or so some of the radial corralites are turning white/dying. Almost as if something was plucking away an individual polyp/eating it. It's not like a "traditional" RTN I've seen in past acros, but something different. The axial corralites seems to be OK and growing.

Was wondering if this is normal with growth or indicative of something more sinister? Maybe not enough flow?

See picture.

Here are some recent measurements:
alk: 9.3
ca: 480
no3: ~1-2
sg: 1.026
po4: 0.08
pH: 8.15

Thank you for any insights!

 

[Backreefing]

Is it all on the side facing the lights ?

 

[Backreefing]

Nice acropora

 

[Lapras]

Thank you! Most of them are, but there are a couple here and there that also on the other shaded side. I can't seem to find a pattern, per se, except that the white is generally on the radial corallites

 

[reacclimating 2 the hobby]

It's not new growth?

 

[jda]

Wild acropora? New tank? This is not a good recipe for success. The dead branch on the right hand side does not look good either.

Even people with very established tanks and lots of experience struggle with wild acro chunks.

 

[Lapras]

I've had the tank a little over two years. Params stable. The acro piece is wild from Diver's Den, had it since April 2018. So this incident started roughly in the past two weeks... incidentally, I did add some emerald crabs, so I will go in tonight with the flashlight to see if they are picking at anything.

 

[Lapras]

Wild acropora? New tank? This is not a good recipe for success. The dead branch on the right hand side does not look good either.

Even people with very established tanks and lots of experience struggle with wild acro chunks.

Right, that dead branch on the right is from a small frag that started to brown, and now unfortunately did not survive. I just haven't pulled it out yet - hoping there might still be something left in the rest of it.

 

[29bonsaireef]

Has it grown at all? Or colored up ever? Still seems to have the shape of a wild Microclados. As said above, wild acros can be a real challenge to keep.

 

[Lapras]

Has it grown at all? Or colored up ever? Still seems to have the shape of a wild Microclados. As said above, wild acros can be a real challenge to keep.

Hi, yes to both. It has colored significantly (used to be dull/whitish pink) now it's more red, and the corallites have this bright red glow in certain light. The growth is slower, it seems, but it's starting to encrust on the base parts which touch the rock.

 

[therman]

I have caught emerald crabs crunching Acropora corallites on multiple occasions. I do not trust them with SPS in any of my tanks.

 

[MarinaP]

Could it be damage from candycane sweepers? Is it close enough, hard to tell from the pic.

 

[Softhammer]

Yeah, candy coral can be violent and send sweepers. I’d repososition that and up your flow as much as possible. Wild corals are accustomed to about ten bazillion gallons per hour!

 

[Lapras]

Thanks all for the replies. THe candy cane is somewhat close, but didn't know that they had sweepers.... I thought their tentacles were short and stubby, but i saw a video of some with longer ones. I will check again tonight