xenia - photosynthetic or not?

[Octoman]

That's the question...

Is xenia photosynthetic or not?

Bob Fenner of wwm insists they are "non-photosynthetic"

Anthony Calfo of rk states that they are "heavily photosynthetic"


What's the deal? Can anyone here back up one side or the other?

[JWarren]

If put in absolute darkness. Will it die or thrive?

Mine do better at the top of the tank, never tried to kill one by putting it in total darkness though.

[Tru2nr]

i have heard they are both they require light to survive but they also require phytoplankton and thats from 3 different lfs and fellow reefers so theres my 2cents

[BigAl07]

My vote is for "Photo-synthetic" because I've seen them climb to the top of the rock up next to the light in a low light situation. When I upgraded the lighting the worked their way back down over the course of a few months and have since left the very top of the rock barren of xenia.

[JWarren]

That's the way I was looking at it too Al.

[cheeks69]

They are photosynthetic !

Bob Fenner of wwm insists they are "non-photosynthetic"

Octoman do you have a link where I can find this statement by Fenner ?

require phytoplankton

This is incorrect !

Anthony Calfo:

Xeniids are also some of the most successful cnidarians in symbiosis with zooxanthellae and seem to derive the overwhelming majority of their "nutrition" from the products of photosynthesis (thriving in controlled culture systems without feeding of any solid matter). That is to say, they do not feed like "hungrier" corals, lacking developed digestive structures to do so. We could also consider and compare the high density of zooxanthellae in Xeniid tissues overall with that of other familiar corals; they share similar densities with the likes of Poritids and Faviids, and they have greater densities than the Pocilloporids and most Acroporids! This is certainly very telling about their strong autotrophic tendencies. Their response to photoperiods reflects this nature in kind. They are highly adaptable to a wide range of light. You will notice that Xeniids placed at depth or under weak illumination will often stretch to spread out their tissues and subsequently their zooxanthellae for better opportunity to catch dim light. Conversely, over-illuminated Xeniids (barring actual light shock or photoinhibition) will contract early in the day to shield their tissues.

[Octoman]

Robert, it is noted a couple times on this FAQ page...
XeniidFAQs

First by Javier about halfway down...
"as you likely know these soft corals are not photosynthetic"

then a little further down by Bob Fenner...
"Hmm, well... not photosynthetic, so not really light... "

[Octoman]

Just found this on another FAQ page, looks like I'm not the only one who was confused...

XeniidFAQs4

Xenia photosynthetic? Yep... very! 1/5/05
Howdy all! Three big time cheers for the WWM crew on a superb site!
<cheers!>
I'm fairly new to the reefkeeping scene (6 obsessed months old) but have kept freshwater planted tanks since I was knee-high to a grasshopper, so you can get as technical as you want to so long as you don't go Einstein on me.
<no fear from me - I'm still wearing Velcro shoes>
I read on the Xeniid FAQ page XeniidSysFAQs) two comments by Bob that Xeniids are not photosynthetic (do a "find on this page" for that word and it's the first two hits).
<simply a typo if so... I didn't peep the thread>
This runs counter to everything I've read about Xeniids.
<correct... they are in fact one of the most nearly/fully autotrophic cnidarians to be found in the hobby>
I have had two small frags in my 15g nano with 80w of PC (50/50 and 6500K) along with star polyps, various shrooms, and a couple small fish and shrimp (all I need now is some crab legs and butter). I'd love to plop some Xenia in my 55 gallon fish/invert tank but it only has 4 NO tubes. What sayest thou?
<the common Xenia elongata (fast pulse Xenia) is very hardy, highly adaptable and will easily live here>
Many thanks for your help, both now and from the site!!!
Cheers! Matt, Charleston SC
<go for it, bro... I'm going to re-adjust my shoes now. Anthony> <<Yikes. RMF>>

[cheeks69]

I hate to disagree with Robert Fenner but I have no doubt they are photosynthetic and from personal experience can attest their tendency to reach for light in systems where the lighting is weak.

[JWarren]

I agree with that observation as well. Plus the fact that they do contain zooxanthella.

Scientific classification
Kingdom: Animalia

Phylum: Cnidaria

Class: Anthozoa

Subclass: Alcyonaria

Order: Alcyonacea

Alcyonacea - Wikipedia, the free encyclopedia

[framerguy]

Just an observation from my system. I have Xenia in the DT that are extending like crazy and multiplying to the point of manual weekly removal. I also have the same species of Xenia in the fuge which has much less light that the DT and they are shrinking and pitiful looking. Same species, same water, same parameters, same feeding, different lighting. Draw your own conclusion.

[JT101]

When my lights are on, my xenias are fully extended and waving in the current...

When the lights go out, they turn into little clumps of black matter...

So, I would have to say they are at least SOMEWHAT photosynthetic.