Zoa ID and a feeding observation

[nathansinger]

Hi all

I was wondering if anyone knows the name for this purple center/yellow skirt zoa on the right side of the pic. Got the branch with those and sweet blue anthelia for only $24. Score!

Secondly, an observation about the zoanthus sociatus in the upper left of the pic. In this reef (65G w/ 2 150W 20K halides and excellent water quality), they don't display a very active feeding response. I notice a little bit of one when I feed Marine Snow or Cyclop-eeze, but nothing at all when I feed mysis or other meaty foods. Weird thing is, I took some of this colony into one of my other reefs (80gal w/ 2x 150w 10K and Act PC's) and they capture mysis aggressively without even being target fed. Anyone have any insight into why this might occur?

http://i61.photobucket.com/albums/h74/nathansinger/zoanthussociatusandpurpleyellowzoos.jpg

 

[surfnvb7]

zoanthus sociatus? huh? i posted a link to something randy holmes wrote a while ago about zoanthids feeding. and its very unlikely that they actually feed. they get all their nutrition through photosynthesis, you can notice this because they are open during the day, and they close at night.

LPS like acans/micros, dendros etc dont open up and extent their tentacles until night, thus dont rely solely on photosynthesis and benefit from supplemental feeding.

zoas closing upon reaction to a stimulus brushing against them could be no more than just that, in my experience they always let go of the food after a while. i've never seen a zoa capture something, then have it completely dissolve and then the zoa opens back up and its gone. there may be an instance of some very large palys (like around 1" or bigger) may feed, just due to their sheer size.

 

[nathansinger]

That's an interesting idea - I'll watch more carefully later today when I feed some shrimp. It doesn't explain, though, why the zoos in this tank wouldn't close due to the stimulus of shrimp brushing against this while the same zoos would close and seem to eat the shrimp in the other tank.

 

[twon8]

i have some zoas that stay open at night, and the ppe=type i have capture and feed as well as some mint blue palys

 

[surfnvb7]

<a href=showthread.php?s=&postid=7444966#post7444966 target=_blank>Originally posted</a> by nathansinger
That's an interesting idea - I'll watch more carefully later today when I feed some shrimp. It doesn't explain, though, why the zoos in this tank wouldn't close due to the stimulus of shrimp brushing against this while the same zoos would close and seem to eat the shrimp in the other tank.

i imagine its most plausible that every different kind of zoa (literally thousands, millions of variations), all vary somewhat in their habbits of feeding or closing up at night (even if its just for a little bit).

as far as the different lighting, it may have to due with the fact of pure intensity. under the 10k's, there is more photosynthesis to fuel the metabolic process of "closing". there is no doubt, that metabollicly, for a small animal like this to move it takes a good bit of energy. so, under brighter light, they may respond faster due to the fact their metabolic responses are operating faster due to more photosynthesis taking place in brighter light.

or, it could simply be the fact that when they close, its just a reeflex reaction. the fact that they actually "catch" the food, may be pure luck that the food happens to be sitting on the polyp when the zoa closes.

most plants in the animal kingdom that actually "eat" bugs, secrete a very acid mucos that actually dissolves the proteins so they can be absorbed through the cell walls. i'm assuming zoas would do the same thing. i HIGHLY doubt they actually envelope the food into their mouths. i've never seen a study where someone has disected a single zoa polyp and documented some sort of digestive system.

but if someone would like to try this little experiment, and document with pictures to show food actually "inside" the zoa, to prove that the zoa actually does take food into its mouth, please do!! i would love to see someone do this. all you would simply do, is feed some food to some zoas, have different batches and a control group, each batch you would let the food sit in the zoa closed up for 5min, 10min, 15min, 20min, 25min, 30min, etc etc. then get a sharp knife, take the zoa (or palys) out, take a direct cross section, and see if the food is actually inside the zoa, or just under the skirt.

this experiment may only be possibly with very large polyps so you can actually see it. i'd love to see someone try to do this.

 

[Azurel]

I have never seen a "Zoanthid" eat at all, even when I fed oyster eggs they didn't respond, they closed up from the water rushing past but opened right back up as soon as I was done. I know palythoas, protopalythoas will feed along with photosynthesis. I have tried many variations of food and types of food and never have the zoanthid polyps taken food or ingested the food. I would have to assume like Surfnvb7, that they get all nutrition from water and light.

 

[msman825]

It's cool how something so pretty feeds off lights and dirty water big grin

 

[Scottkelly911]

I've seen a few of my zoanthids take in food and close up around the food. Not often, but I see it occassionally.