Disappearing Zoas

[Dominican]

Okay, so there are a number of these threads here and on other forums, but none seem to have a definitive answer, so here goes.. (This happened a few weeks ago; just getting around to asking about it..)

I have some AOG's that have never been touched (to this day), but every other type of Zoa I've had was wiped off the face of my marine microcosm over the course of a few nights.. Everything was fine (for months) and I had a few different colonies going, then - not corresponding with a new fish or other addition to the tank - each night a cluster would disappear.. And I mean up to 10 heads in a night (!). And the rock underneath them looked like it had been ground with a scouring pad..

Now, I'm aware that fish go rogue, that there are pest nudibranchs, giant amphipods, and nasty little snails that will attack zoas, but are they really able to mow down such large swaths of biomass in one night? I thought my urchins were eating them and even banished a tuxedo to the sump for a while. It didn't help..

All the threads out there talk about dipping the zoa rocks in FW, and a number of different products to kill the nasties, but I've got a ton of rock. Not one of these threads has a post where the originator follows up saying, I figured it out; it was a ____!

And I dunno what's up with my AOG's, they must taste like sh*t. lol..

Anybody heard of non-anecdotal, definitive Root Cause on any of these mystery midnight zoa munching cases? Sorry for the book..

[rrasco]

I've been trying to figure something similar out myself. I don't have them up and gone overnight with the evidence you do, but in my 29 zoas that used to thrive would shrivel up and never open. I only actually lost one colony of zoas completely, but the rest just barely open if at all. I moved them to the new 105 about 6 weeks ago and they seem to be starting to recover. The 29 was running year old T5s so I always kind of attributed it to that, but I never knew for sure.

Since you mentioned it, I did see a rather large molt from what I believed to be a giant pod last night; but that is purely speculation. I was surprised because I didn't know pods could get that big, about 1/4". Do pods molt?

I have done some research on it and I just try to keep them clean as possible. Blowing off any algae (or possibly zooanthelle, but I think it's dinos/cyano on them) and they seem to be doing better. My palys seem to do okay, it's just the zoas. Currently it's 3 different zoa colonies that are hanging on.

[JamieP]

I had a large Halloween hermit that went straight for a colony of AOG's. The first day I noticed a large bare spot and he was nearby. I didn't think he could do it, but the next day I noticed another larger patch gone and he was in the middle of them. Once I removed him, no more problems. He probably ate 5 heads the first day and 10 the second.

[Dominican]

@rrosco: I've heard of 1/4" pods on other forums. Some that supposedly eat zoas.. but I don't know if they molt. Good question! Also, I just recently changed all my lights 3x250 Phoenix 14k and 2 superactinic T12s. Thought about that as being a factor, but since lights don't have teeth.. lol

@JamieP: That could be a possibility. Some crab I haven't seen.. or even a hermit that I have seen but that I wouldn't suspect.. hmm..

Just wish I had a smoking gun. Might have to buy some scrub zoas and do a red-light stakeout. Everytime I read that someone is going to do this, I don't ever see a follow up if they found anything.. I'll post more when I get some. Whatever it is, ate some blue tubbs :( , orange skirts, and fruit loops. I better get some inexpensive bait!

[rrasco]

From the research I have done, the most common occurrence of disappearing zoas has to do with some type of fungus. People seemed to have the most success cleaning them off daily and some had success with dip treatments. One of them was iodine I believe. And some zoas are effected and others are not. That's why I have been keeping mine clean, but I don't think it's a fungus. Mine were globally effected. Of course, none of this is of use to you since it seems something is eating yours.

I have not seen a pod that big in my tank, there are several decent sized ones, maybe 1/16" or 1/8"...I just saw what I believe to be a molt which was that size. I really don't know what it was, I was going to make a post about it...but I didn't.

[Dominican]

Ok, so here's the official update and resolution to my dilemma. The culprit? My beautiful orange spotted rabbitfish. After going a couple months with no zoas in the tank, I ran across some hornets just I couldn't pass up. So I made a little shark cage for them, covered them and waited. I first noticed my yellow cuke hanging around the cage, so I put him in the sump - I didn't really think it could be him but wanted to remove the variable... I waited some more, because if it was snails or parasites, they had full access to the zoas and I'd start to see an impact.. Nothing.. I waited some more, and when I was sure they were okay, I pulled the cage off and watched. Not a few minutes later, the rabbit came over and ripped a piece off of one of the outermost heads!

That rabbit is now back at the LFS. Sucks too, cause I loved that fish! Oh well, this hobby is full of trade-offs!

Anyone got any blue-tubbs for sale?? lol

[allan]

Man, when I first started up I had a colony of texas trash that my rabbit fish went after. I got rid of the fish before I realized that he was helping me out.

[Dominican]

That's so funny, Allan. When this all started, my tank was overrun by dark green button polyps (Protopalythoa). They were everywhere and driving me nuts. Now, only one isolated rock with these buggers remains. Strange how I didn't even realize it until you said this! Thanks for reminding me to focus on the positive.. lol

[ErikH]

Get rid of that rock before they grow any more!!!!

[Dominican]

Erik, you're so right; I should ditch that rock. It's at the bottom of the jenga pile though! I'll take a look at it when I get home.. Maybe I can play some "operation."