Cause of zoa loss?

[hockyfn30]

I was wondering if anybody could tell me from these pictures what could be the cause of this zoa death, be it tankmate feasting on them or an environment problem.

For fish, I have 2 ocellaris clownfish and 3 blue chromis. As for the inverts, 3 emerald crabs, the largest being a little more than a half inch across the body, some blue leg and scarlet hermit crabs, 2 peppermint shrimp, 2 brittle stars and some astrea and necarrius snails.

before

after

the polyps around the outside seems to be surviving, the middle has the most loss

before (bottom left)

after

 

[killingseed]

3 emerald crabs may eat polyps , peppermint shrimp may eat polyps, 2 brittle stars could at the most be irritating them.

i personaly would start by removing the crabs and shrimps.
what are your water par.

 

[hockyfn30]

water parameters - Ammonia/Nitrite 0, Nitrate less than 10, pH 8.0, Cal 420, Alk 11 dkh, salinity 1.026, Temp 79

 

[Lytehouse]

<a href=showthread.php?s=&postid=11251196#post11251196 target=_blank>Originally posted</a> by killingseed
3 emerald crabs may eat polyps , peppermint shrimp may eat polyps, 2 brittle stars could at the most be irritating them.

i personaly would start by removing the crabs and shrimps.
what are your water par.

I agree they can be opportunistic feeders of zoa/paly's. No proof, but IMO they are less likely to feed on our critters if they have plenty of other food sources. Do you feed the crabs specifically? Something like pellets that hit the bottom of the tank and don't get picked up by the fish first?

 

[hockyfn30]

No I don't feed anything specifically for the crabs, just anything that is not eaten by the fish that they can scavenge for. I would be worried about "overfeeding" the tank and having uneaten food that could mess up the tank parameters if I were to suppliment the food for the crabs.

So is it a consensus that something is eating the zoas and that they are not just dying off due to some unknown cause. Seeing the small amount of tissue that still remains on the rock had me leaning towards that answer also. Now I have to figure out where these crabs are gonna go before I can watch to see if the zoas recuperate.

 

[Lytehouse]

feeding

feeding

I don't think you are going to screw up water paramaters by dropping in a few pellets for the crabs every couple days or so, especially if you have a good clean up crew of snails, hermits etc.... It could certainly be easier to move the zoa frag and try feeding a little over tearing out the rock work trying to catch 3 crabs.

Good luck..........

 

[hockyfn30]

Would it only be the emerald crabs that are guilty or could any of the crabs (scarlet hermit, blue leg hermit) be munching on the zoas if their hungry?

If its only the emerald, I don't think it will be that big of a problem removing them to see if they are the culprit. If its all crabs, then I will consider the pellets to keep everybody happy.

 

[Don Lino]

To me, these frags look like they just shriveled up and died. I had this issue with numerous Bam Bam frags and noticed changes to this when I began dosing Tropic Marin iodine into my system. I noticed a bunch of my zoas do a 360 turn around when I began this. What I do is every week I dose 5 drops into my 120gal system.

 

[G.SMITHII]

in your very last pic, it would seem that the colony of zoos is covered in flatworms.

do flatworms eat zoos?