Something eating bases of zoas

[SwampCanary]

Something has been eating the bases off my zoas. The tops fall to the bottom of the tank and do fine when moved to the quarantine tank. I lost two medium colonies in a couple of days, and it seems to happen mostly at night. I've searched for predators, but am totally baffled.

Then yesterday I noticed a couple of my palys are missing their heads! The stems are still there.

What eats only the base of zoas and only the heads of palys?

 

[organism]

There's some kind of fungus that does that, is there like some powdery brown looking stuff on the bottoms of the palys? Otherwise could be fish nipping at them, or if you're not measuring your salinity with a refractometer calibrated with calibration fluid then it could be that it's too high...

 

[Dexters Reef]

I highly recommend looking again for zoanthid eating nudibranches. They come out mainly at night after all lights have been off for a while. They are tiny! And to make things worse, thy absorb the color of the zoos they eat so they blend in better

They eat entire zoanthids and most ignore palythoas, but might be nipping at them.

Is this happening only in certain colonies? can you dip the rock in revive to see if any pests fall off?

 

[SwampCanary]

It pretty much destroyed two adjacent colonies of zoas, but left a third untouched. I'll do a midnight raid for nudis. Part of the problem is that I can't remove the zoas for dipping without completely disassembling the tank.

No fish in the tank, just CUC. Haven't seen anything that looks fungus-like. Salinity was rather high, so I corrected that.

 

[AcanQueen]

It could be zoa spiders- they're a nasty little pest that burrows into the base of the zoa and eats it from the inside out. When the spider reaches full size they're easier to see and tend to sit across the top of the polyp. Once again they're another pest that comes out at night so keep an eye out for them while you're watching for the nudis.

Another possibility is a hungry crab with a passion for polyps?

 

[650-IS350]

http://www.coralpedia.com/index.php?module=Gallery2&g2_itemId=384

 

[reefwars]

They eat entire zoanthids and most ignore palythoas, but might be nipping at them.

zoa eating nudibranchs do not touch palythoas , nudibranch's are target predators they target a certain food source and only that food, they may attack some of the larger zoanthus(hence their name) but they will not eat or go near a palythoa or protopaly.

 

[Dexters Reef]

I found one the other day on a palythoa colony. I'm pretty sure they are paly's, they have a matting base, and stalks and are larger than zoos. I don't know if it was eating the paly, but I did pull it off of one. The paly colony is in between two large zoanthid colonies, so maybe I caught it in transit?

 

[A. Grandis]

I found one the other day on a palythoa colony. I'm pretty sure they are paly's, they have a matting base, and stalks and are larger than zoos. I don't know if it was eating the paly, but I did pull it off of one. The paly colony is in between two large zoanthid colonies, so maybe I caught it in transit?

Do you have a picture of the "paly" colony please?

I'm learning something here... Never had spiders nor nudis in my life. Only read about them.

Pics please...

Grandis.

 

[A. Grandis]

There's some kind of fungus that does that, is there like some powdery brown looking stuff on the bottoms of the palys? Otherwise could be fish nipping at them, or if you're not measuring your salinity with a refractometer calibrated with calibration fluid then it could be that it's too high...

What would be exactly the symptoms of the high salinity you refer and how high is high, please?
Thanks,

Grandis.

 

[A. Grandis]

It could be zoa spiders- they're a nasty little pest that burrows into the base of the zoa and eats it from the inside out. When the spider reaches full size they're easier to see and tend to sit across the top of the polyp. Once again they're another pest that comes out at night so keep an eye out for them while you're watching for the nudis.

Another possibility is a hungry crab with a passion for polyps?

From the inside out?
How is that?
I would think they begin to eat them out and make a whole.
That would be from outside in.
I never had spiders.

Grandis.

 

[A. Grandis]

Something has been eating the bases off my zoas. The tops fall to the bottom of the tank and do fine when moved to the quarantine tank. I lost two medium colonies in a couple of days, and it seems to happen mostly at night. I've searched for predators, but am totally baffled.

Then yesterday I noticed a couple of my palys are missing their heads! The stems are still there.

What eats only the base of zoas and only the heads of palys?

I've never heard about damaged bases.
The times I've had damaged heads the problem was my Angelfish.

Grandis.

 

[Dexters Reef]

Do you have a picture of the "paly" colony please?

I'm learning something here... Never had spiders nor nudis in my life. Only read about them.

Pics please...

Grandis.

Hi,

My mistake actually, the "paly" in question was my armor of gods colony, but upon further research most people conclude this is actually a larger zoa, although it is sold under both names.

Heres a pic anyways!

 

[A. Grandis]

Hi,

My mistake actually, the "paly" in question was my armor of gods colony, but upon further research most people conclude this is actually a larger zoa, although it is sold under both names.

Heres a pic anyways!

Yes, that's probably a Zoanthus sp.
Many people think some of the Zoanthus spp. are actually Palythoa or Protopalythoa spp.
Specially when the Zoanthus have bigger oral discs, longer skirts or stalks, some really think they are "palys".
That's still a common mistake.

Grandis.

 

[Dexters Reef]

Just to add, I do have a paly colony (palythoas grandis, 2" polyps) and I can confirm I have not found a nudi on it at all

So to the op, if you are sure you have true palys being eaten, I would not say it is the nudibranches I originally suggested.

 

[AcanQueen]

From the inside out?
How is that?
I would think they begin to eat them out and make a whole.
That would be from outside in.
I never had spiders.

Grandis.

Yep they really do eat the zoa from the inside out...

My experience with them was when they came in on a wild colony and as I had not encountered them before it was a bit of a mystery why the zoa polyps kept disappearing.

The usual dips including fresh water didn't seem to make much difference but I later I realised they were actually growing inside the polyps. The tell-tale sign was a small hole in the base of the polyp. Then I noticed that some of the polyps started to go pale almost translucent and after slicing one of them open out popped a juvenile spider. The final stage is when they burst out leaving a headless withered zoa - think Alien :eek1:. When the spiders reach full size they tend to hide under the matt or base of the zoa or any small crevice only coming out at night to feed.

It took me a while to eliminate them and they certainly gave me a run for my money!

 

[A. Grandis]

Yep they really do eat the zoa from the inside out...

My experience with them was when they came in on a wild colony and as I had not encountered them before it was a bit of a mystery why the zoa polyps kept disappearing.

The usual dips including fresh water didn't seem to make much difference but I later I realised they were actually growing inside the polyps. The tell-tale sign was a small hole in the base of the polyp. Then I noticed that some of the polyps started to go pale almost translucent and after slicing one of them open out popped a juvenile spider. The final stage is when they burst out leaving a headless withered zoa - think Alien :eek1:. When the spiders reach full size they tend to hide under the matt or base of the zoa or any small crevice only coming out at night to feed.

It took me a while to eliminate them and they certainly gave me a run for my money!

I've never had spiders in my life nor searched for that, so I'm really surprised about how they eat the polyps. That's very weird!!
There must be a medicine to be used for spiders.

Grandis.