Unknown Coral Species Possibly Invertebrate?
(Hee-hee'¦aren't they all?) -- 04/20/09
I'm sort of embarrassed to ask a question about a species
identification, especially with so much information available
over the net, at the LFS or the library. But in all honesty, I
have Googled for hours and have stopped in every fish store to
ask questions and still have no answers. (didn't make it to
I bought what I thought was a Xenia in one of the many stores
that I frequent, I bought it thinking that I was well read and
knowledgeable enough to take care of a new addition to my
I picked out what I wanted, a light brown healthy looking Xenia
with tentacles that started at the foot that was buried in the
sand, and extended up about 3 inches.
<<Not a Xenia then'¦are 'encrusting'
The shape is like a Christmas tree,
<<And this is your first clue>>
full at the bottom, gradually becoming smaller at the top. I
walked away from the specimen tank to defend a poor little clown
fish that was being picked on by bigger bullies and did not
observe the employees putting my prize of the day in the plastic
container, so imagine my surprise when I get home and see this
brown looking morel mushroom looking thing suspended in
<<A good analogy>>
(pick morels in woods every spring) Where's the waving
tentacles and the little fingers at the end of the tentacles? So
I fight the urge to drive back to the store, 50 miles away, plus
the store was closed for the evening and I removed the brown
wilting looking mushroom thing from the bag and have no clue what
to do with it because it has a soft foot with nothing attached to
weigh it down or prop it up.
First time I have had to deal with this, I always get coral that
are attached to frag or rock. So I bury the foot in the sand,
<<A good move'¦>>
until the little bugger is somewhat upright. An hour or so later
the tentacles start to creep out of the cap, woo hoo!!, the fish
store people didn't switch a slimy mushroom for my Xenia. I
turned off the tank light and went to bed. Next morning, I come
downstairs and go straight to my tank and my poor half Shroom and
Xenia are gone.
<<Clue number three'¦>>
Nothing there, vanished. I start on the morning tank regimen and
come back an hour later to turn the skimmer back on and low and
behold there is my Xenia waving around in the current.
<<A good sign>>
Now I am just dying to know how my Houdini Xenia just disappears
and reappears, so I check the tank every hour or so and about 8
hours later, he starts shrinking, pulls all his tentacles so far
into that funny little mushroom cap that you wouldn't even
know that he had tentacles and he just got smaller and smaller,
burying himself in the sand, until he disappeared.
Next morning he pops up right against the tank wall, about 3
inches away from where he buried himself. I sort of push him a
couple of inches away from the wall
<<Mmm, careful'¦best to let this critter pick its
and he happily waved his Houdini arms and fingers around for
another 8 hours and disappears. Next morning he pops back up
against the tank wall, where he is currently residing.
What do I have?
<<The description and behavior you describe sounds very
much like a Sphaerella or Studeriotes species of soft coral
common names are Christmas Tree Coral, and Medusa
I cannot find any information on Xenia's that retract their
tentacles and bury themselves in the sand.
<<Is not a Xeniid>>
I can't find any information about an invertebrate with
tentacles like a Xenia.
<<Try a Google search on the Latin and common names I
listed and see what you think>>
All the fish store employees just look at me funny and think that
I am a twit who shouldn't be within 10 feet of an
<<But, they don't know what this coral is
Do I care for it like a Xenia?
<<Mmm, no'¦this is an azooxanthellate coral that
requires direct supplemental feeding'¦and much like
Dendronephthya species, is not easy to keep. To be honest, I
don't give you good odds for maintaining this animal for long
as it will likely starve to death in a few weeks to months. You
can try feeding small meaty foods like Cyclops-Eeze, Rotifers,
etc'¦but in my experiences these animals always slowly
shrivel away and die. I think the best thing would be to return
this coral to the LFS for a refund/store credit>>
Houdini seems to be doing okay for now, but I'm concerned
that it will decline in the future if I am not treating it
accordingly to its species.
<<Even so'¦there's not a lot of info on the
'successful' care of this genus>>
I will try to send photos of his tricks, it's just a matter
of catching him doing them.
Thank You for any information at all.
<<Sorry it's not better info'¦
Re: Unknown Coral Species Possibly Invertebrate?
(Hee-hee'¦aren't they all?) -- 04/20/09
Thank you so much for the quick response.
I apologize for the ignorance.
<<No worries my friend'¦you're smarter than
you were yesterday, eh? [grin]>>
I really did research Xenia's but I guess, I am not
knowledgeable enough to pick them out in a line-up.
<<An honest mistake, I'm sure>>
I live outside of Cincinnati and bought the coral in Dayton and
although I could probably trade it or get my money back, do I
really want to give Houdini back to a store that sold him as a
Xenia in the first place?
<<Mmm, well'¦one of the best things we can do is
to educate ourselves/others not to purchase such
animals'¦or to return them when done after-the-fact. If
the store can't sell it, then hopefully they won't order
it in next time>>
Personally, I would rather lose the money as lesson learned and
give him to someone who is equipped and knowledgeable enough to
take care of him.
<<A fine sentiment'¦but what about the next time,
and the next time, and the next time'¦?>>
(let me know if you know of someone)
<<Unfortunately there are few folks willing or able to
devote to and maintain the specialized setup
I included a picture of Houdini and I briefly researched both
Studeriotes and Sphaerella as well as Medusa and Christmas tree
corals. I haven't been able to find a photo that looks like
mine but the described behaviors are on the nose.
<<Ah yes! It is now clear that what you have here is a
species of Cavernularia'¦likely C. obese. Commonly
called Sea Pen (though there are several similar genera/species
also referred to re)>>
If you believe that it is not a Studeriotes or Sphaerella, then
I'll try to take some photos of his disappearing antics later
<<Not necessary'¦am certain this is a Cavernularia
based on your earlier description and these photos. And the
prognosis may not be as dire as earlier perceived. Many species
of Sea Pen are nocturnal and azooxanthellate as described in our
earlier exchange'¦the fact that this specimen comes out
when the lights are on is a good indicator that it is a
If you want, you can tell me that I wasn't a knuckle head for
thinking that it was a Xenia. Or you can tell me how you really
feel and call me a raving Hulk sized knuckle head.
<<Mmm, not at all'¦ There 'is' a
remarkable resemblance'¦especially to the
Just a note, the folks at the fish stores had no idea what it
was, one guy said that it could be a wild anemone and then showed
<<(sigh)'¦ Sad indeed'¦>>
Also, please do not think poorly of my tank upkeep.
I have been gone for the last two weeks to take care of sick
<<Sorry to hear>>
I have only been home twice these last two weeks, I tell my boys
that I missed them and that is why I made the over 200 mile drive
back home, but I really just want to check on my aquarium to make
sure that everything is still alive.
<<Hee-hee'¦I'll never tell!>
This time I had a red algae bloom. The boys had been leaving the
light on for too long, which is better than the last time when
they hadn't turned the protein skimmer on for almost a
<<Hmm, sounds like a lighting timer is in order (your tank
really would appreciate the regularity)'¦and maybe
someone from the local aquarium club to check in once in awhile
(if a possibility)>>
I have to leave again for another week and am terrified about
what I'll find when I come home again.
Crossing my fingers and praying that they take care of the
Thank you so much for your help.
<<Always welcome'¦safe travels. Eric