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View Full Version : Zooanthids - Predators or Illness



SeaDawg
03-18-2008, 11:45 AM
Can anyone ID these hitchhikers and let me know if they are harmful?

One very large zooanthid colony has thinned out severly over several days and I caught these guys dancing around all over them. One of them I presume is a nudibranch, but after visiting several ID sights with LOTS of photos, was unable to ID it. The body is black and the little branches are neon green. The quantity of them has increased and the only place I see them is on the coral. I have picked them off on a couple of occasions and they seem to disintegrate. The other guy looks like it has a hard shell with pincers or barbs on the back end.

There were a couple of another type critter crawling around the colony that moved so fast it was impossible to photo and it looked like some sort of spider, crab, beetle, shrimp thingy that scurries about. That bug is slightly larger than the photographed invaders.

My water parameters are all within the normal published ranges. Only recent change is I started adding PhytoFeast-Live thinking it would help to propogate some of the smaller frags since they are also taking a beating and a few have died. A also have a few palys that seem unaffected. No fish in the tank at the moment. Inverts include a couple astrea snails, couple emerald mithrax crabs, and scarlet reef hermit, all which seem to be happy and content with cleaning up rocks and glass. Bristle stars and worms seem to be everywhere, to the point of alarm. Thinking I may add a six line wrasse to keep the popluation outbreak under control.

Help?! Thanks!

BadRoma1
03-18-2008, 11:59 AM
that thing in the first pic sure looks like it's eating your zoa.

Grins
03-18-2008, 12:09 PM
You have aeolid nudibranches they are not fun to eradicate because of the egg spirals they lay. I managted it with lots of FW dips. The white one looks a bit like an isopod.

SeaDawg
03-18-2008, 5:19 PM
Thanks Grins. The LFS suggested using a dip of Lugol's Solution, but then again I guess they're in the business to sell stuff. Of course I can use it to condition the tank. Does anyone have an opinion if a FW dip is better or worse than the iodine (cost aside) and why?

Grins
03-18-2008, 5:26 PM
Lugols is great as a preventative and as a cure. I wanted to try the FW though and it worked (after lots of peeving the zoas off)

Amphiprion
03-18-2008, 7:11 PM
The little sphaeromatid isopod is harmless. The zoanthid-eating aeolids are not.

Grins
03-18-2008, 7:19 PM
So it was an isopod. I though so but the tail end was throwing me.

leocom2000
03-19-2008, 3:32 AM
I think this is interesting:
http://reefkeeping.com/issues/2005-05/rs/index.php

"Human injuries from contact with aeolid cerata (http://www.seaslugforum.net/factsheet.cfm?base=glauatla) are not uncommon."

Amphiprion
03-19-2008, 8:00 AM
Those aeolids are very different and typically feed on cnidarians with significantly more potent nematocysts. While zoanthid eating aeolids can and do concentrate the nematocysts, they aren't potent enough to be an issue.

You--or a mod--may want to do something about the second link--it doesn't have anything to do with sea slugs... :perv: :eek:

Reefscape
03-19-2008, 8:10 AM
Those aeolids are very different and typically feed on cnidarians with significantly more potent nematocysts. While zoanthid eating aeolids can and do concentrate the nematocysts, they aren't potent enough to be an issue.

You--or a mod--may want to do something about the second link--it doesn't have anything to do with sea slugs... :perv: :eek:


All sorted :)

SeaDawg
03-19-2008, 11:23 AM
Thanks to all. Yes some interesting reading. I thought they were quite beautifull and after expiencing how lethal they can be to the coral surmised the coloring was a camoflage to avoid predators. I'll do due diligence and remove them as I find them.