Case of the disappearing yellow polyps

[Steveb]

I have had a "paly/zoanthid combo rock" in the tank for about 2 months now. The rock has several different types of polyps on it composed of zoanthid's, a group of protopalythoa, a group of parazoanthis, some pachyclauvaria, and some clauvaria on it. Over the past couple of weeks I have noticed that the parazoanthis (yellow polyps) have begun to decline. They just close up, shrink and eventually disappear. A few of the zoanthid's on the rock have done the same thing but not nearly to the scale of the yellow polyps (also have other zoanthid frags throughout the tank that are still doing fine). Have gone from approx. 20 yellow polyps to four.......

Combo rock placement is at bottom of tank.

I have not seen any critters on the rock other than a bristle worm on the rock this evening.

Here are the tank water parameters... (sorry tried to get it aligned but not successful)

20-Aug 30-Aug
PH 8.10 8.16
Temp 77.7 76.4
SG 1.026 1.025
NO3 4.00 1.00
Ca 430.00 435.00
KH/Alk (dkH) 9.90 10.00
Mg 1245.00 1477.50
P04 0.00 0.00

Photoperiod 12.00 hours (Coralife 3 31w actinic, 1 10k) -- tank is an Aqueon 36 gallon bow front 21" deep.

Any thoughts?

 

[kingfisher62]

I have had similar issues with them. Sometimes they multiply like crazy and sometimes they start melting away. Have not figured it out yet so I will be tagging along here.

 

[Rich123]

Do you have peperment shrimp? My peperment shrimp eat mine when I stuck it in my tank. Maybe he thought it was aiptasia.

 

[Jarred1]

i have had yellow polyps do that to me, they were in high flow and looked fine but started to melt away. i moved them to almost no flow and now i only have 4 left out of about 100

 

[rogersb]

It might be a blessing in disguise. I had yellow polyps go nuts and start killing everything in their wake. I had to frag, frag, and refrag them, then use aquamend and putty over large sections of the rocks they were on just to get rid of them.

 

[Steveb]

I don't have any fish or shrimp that would be preying on them.... go figure I cant grow weeds :fun4:

 

[D.J.'s reef]

ive tried them 3 times and same results everytime......and its only them that i have issues with.....

 

[sebastian903]

maybe a snail or urchin

 

[Steveb]

Well I think we discovered the culprit! My son was checking over the rock this evening and saw/captured a zoanthid eating nudibranch. We have looked over the rock pretty close now and don't see any others and no indications of the white egg cases on the rock or surrounding zoanthids. All of the other zoanthid frags appear to be fine - took the tweezers an brushed them so they all closed and then examined them.

Think we need to pull them all out and dip or just take a wait and see?