Acans seem to hollow out and recede

[BOMPH]

It seems to be that one coral that I can't seem to get to grow. I have 5 or six different colonies of various sizes, the biggest being around 4 inches in diameter. I have noticed that they don't really grow all that well, and all of them, over time seem to have a polyp or two start to hollow out from the center. This has been going on for a good 6 months. The entire colony doesn't seem to die off, just a polyp here and there.

My current params are: SG1.025, and 9ALK, 450Ca, 1400Mg, 0 PO4, ~2 NO3, all measured with Salifert kits.


Thoughts? Anything else I should test for that this particular symptom might indicate I need to pay attention to? ( i also just got I2, K, and Fe test kits from Red Sea that I haven't gotten around to yet )

 

[aromano]

what kind of flow are they getting? They dont like a whole lot of flow. Are you feeding them at all?

 

[BOMPH]

what kind of flow are they getting? They dont like a whole lot of flow. Are you feeding them at all?

I have them all on the bottom, some on sand, some mounted on rock. I would say their flow is moderate, not too high down there. I do feed, a mix of rotifers/cyclopeeze/Oyster Feast/Rods Food, Brine/Mysis that I throw into a cup all together and feed to everything in the tank, which is SPS and LPS, a good 40 different specimens all together. Dang Fish take most of it!

 

[Bpb]

I have had the same experience. Used to have nearly a dozen fast growing real nice acan colonies, and suddenly out of nowhere they started hollowing out on the mouth areas and then just melting away from the perimeter of each colony. All were either traded away or died, and those that were traded died in the new owners tanks in the same manner. Never found out why. Never bought more after that

 

[Tweaked]

I have had the same experience. Used to have nearly a dozen fast growing real nice acan colonies, and suddenly out of nowhere they started hollowing out on the mouth areas and then just melting away from the perimeter of each colony. All were either traded away or died, and those that were traded died in the new owners tanks in the same manner. Never found out why. Never bought more after that

Exactly my experience. That and most turn red no matter the starting color for me. I have since retried with a micromussen colony.

 

[Philly_Reefer]

no fish predation/invert?

 

[DEA Coral]

I noticed that my hermits or peppermint shrimp will take the food out of the polyp if I do not feed them first. Twice now, one or the other damaged two different frags doing this. I thought I had a serious issue but the damaged head recovered after a dip and a change in feeding routine.