zoas disintegrating...or being eaten??

[sardonicscorpio]

I am starting to believe that something wicked is in my tank., but I have seen nothing. Heres the deal...I have zoas that disappear in a week. I had a rock with 30-50 polyps on it, everything great for 6 months, and then they just disappear within a week last month. I had another colony of 20-30 safecracker zoas disappear this week. There were some clear tunicate things growing up right next to them, and they are also gone. They were there since last August, and I can see the last bits of them on the rock looking ragged around the edges like something was munching on them. I have 3 types of palys and 4 types of zoos left - my tubs blues havent been touched (hallelujah), but now I'm noticing another group is missing a polyp or two...at first I thought I had the disintegrating zoa problem, but all my water params are where they need to be, and if that were the case why are my other zoas ok?
I have been combing the tank looking for zoa eating nudibranchs, spiders, etc...I also have a sand sifting star that lost an arm, and it looks like he was attacked by something. I haven't added anything but a couple of anthias to the tank in months, and I haven't seen my shrimps (cleaner and peppermint) or fish bothering my zoas. I'm baffled!!
ph 8.1
sg 1.026
alk 11
trates/trites/phos 0
temp 78
Any ideas???? I haven't been able to trap anything...

 

[650-IS350]

try looking for fireworms or the other really bad coral/fish eating worm that can get upwards of 5 + feet in a tank.

 

[sardonicscorpio]

I do have at least 1 bristleworm, but its the reefsafe non fireworm...I have seen no evidence of anything else.

 

[livingcorals]

Also check for Sea Spiders.
They bite!

 

[sardonicscorpio]

If there were spiders, would they be there in the lights or only at night? I've been watching the tank under moonlights, and haven't seen anything yet...

 

[kindafun]

Tagging along, I hope you get this figured out.

 

[livingcorals]

Depends on how strong your lights are but sometimes yes can be seen with the lights on.
There can be the size of a BB to half a dime.
Best of luck

 

[Pufferpunk]

Zoanthid Predators, Irritaters & Diseases: http://www.zoaid.com/index.php?module=Gallery2&g2_itemId=384

 

[ros_sco]

I had a gorilla crab (hairy legs, black pointed claws) suddenly start eating my zoas. 10-20 polyps per night. It came out only at night.

 

[thecichlidpleco]

It is tough to say it is this or that unless you have actually seen a spider. They could be melting and pods and bristleworms are feeding on the dying flesh, or they could just be melting. I had colonies do great, always full and open, then close up no reason and look like they are about to die. I just switched to another tank with 70w MH which bleaches most lps I put under it, and they have grown and done great.

 

[Pufferpunk]

My zoas stopped melting after dosing with vitamin C daily. Now, they look great!