FAQs on Identification of Stinging-Celled
Related Articles: Cnidarians, Water Flow, How Much
Related FAQs: Cnidarian IDs 1, Cnidarian IDs 2, Cnidarian IDs 3,
Cnidarians ID 4,
Cnidarians ID 5,
6, Cnidarian ID 7, Cnidarian ID 8, Cnidarian ID 9, Cnidarian ID 10,
Cnidarian ID 11,
Cnidarian ID 12, Cnidarian ID 13, Cnidarian ID
14, Cnidarian ID
15, Cnidarian ID
16, Cnidarian ID 18, Cnidarian ID 19, Cnidarian ID 20, Cnidarian ID 21, Cnidarian ID 22, Cnidarian ID 23, Cnidarian ID 24, Cnidarian ID 26, Cnidarian ID 27, Cnidarian ID 28,
Cnidarian ID 28,
Cnidarian ID 30,
Cnidarian ID 31,
& Anemone ID 1, Aiptasia
ID 1, Stony Coral ID
1, Mushroom Identification,
Soft Coral ID, Alcyoniid ID, Xeniid ID,
Unknown Coral Species Possibly Invertebrate?
(Hee-hee'¦aren't they all?) --
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 own spot>>
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?) --
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
(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
Hitchhiker ID: No picture, but probably a Zoanthid by the
I apologize for how vague this question may be but that's actually
why I'm turning to you.
<Well, we try...:-) >
We have a 55 gallon corner aquarium roughly 2 months old.
<Welcome to the hobby.>
We have added around 30lb of varied live rock, a shallow 2 inch sand
bed, around 20 snails (Nerite, Cerith, margarita and Stomatella), 2
peppermint shrimp and 1 diamond watchman goby. These are all of our
clean up crew.
All water param.s are normal: 78 degrees, 0 nitrites, 0 nitrates, 0
phosphates, 400 calcium.
<Sounds good so far.>
We have a slight hair algae issue which may be contributing to our nice
param.s but doesn't appear out of control and we're trying to
starve it out with good quality water and slightly reducing the
<I'm one of the few who will say as long as it is controlled, it
can actually be rather attractive.>
Now the question. As a brand new hobbyist I watch every inch of the
rock obsessively to find new and interesting things as soon as they pop
up. Or so I thought... Today at the top portion of one of the live
rocks I found what looks like a little mushroom patch/grove. I reached
in an gently felt it and each cap feels soft but firm. Most of the caps
(I don't know what else to call them) are brown with 1 of the
largest (and slightly offset...1/4 inch or so) is a medium to bright
<Difficult to say with any certainty without a picture, but based
upon your description, I would hazard a guess that they are
I've tried search for 'mushroom' and only get mushroom
coral. I've tried search on hitch hikers and obviously get a wide
range of snails, crab, worms and so forth. I don't know what else
to do to narrow my search down. Have you heard of anything like this or
do you have any ideas how I might better search for it? I've tried
taking pictures but (probably due to the intense curve of the tank) I
can't seem to get anything clear.
<The macro setting on your camera (usually depicted by a single
flower) is best, do not use a flash, and indirect lighting - a
flashlight works well.>
Any help would be appreciated and again my apologies for the
<Do check the following pages, I've listed them in order of
likelihood based upon your description.
Re: Newbie Question 04/05/09
Okay, I got some pics, but they are the greatest, I had a flash
light in one hand and the camera in the other! Please let me know
if this is aiptasia so if it is I can get it out of my tank. It
is still only coming out at night. All of the tentacles have
about 4 stripes on them, brown and translucent.
<Well, they don't look like aiptasia... but are possibly
majano anemones (another kind of pest anemone). But it's hard
to say for sure... I hope BobF or Lynn will comment if they have
<<Doe look like Anemonia... but only out at night? Is there
a stony skeleton/corallite visible? RMF>>
Re: Newbie Question, Cnid. ID 4/7/09
That was supposed to be aren't the best, so much for a 5am
email! Okay, I will leave them for now and watch, I will update
you if anything changes or if I can get better pics!
<Good idea, as BobF noted... it is odd that they only come out
at night... and suggests that it might be some kind of coral.
We'll see I guess...>
And my levels have dropped back to 0!
Thanks again for all your help and dedication to the site!! It is
great and has helped me so much!!
Aiptasia? Please Tell Me It Isn't So! --
I hope everyone there is having a great weekend so far.
<<Can only speak for myself but yes, not so bad>>
I absolutely love WWM and have found it extremely helpful.
<<Ahh'¦is redeeming to know>>
I was looking in my tank tonight and noticed these creatures. The
first thing that popped into my head was ahhh no is this the
<<Hmm'¦looking at the picture, I'm not
I just started my tank about 5 weeks or so ago and have been
working on getting the stuff together slowly. I only have around
20 lbs. of live rock that I purchased from my LFS. There are
around 5 or 6 of these on the rock so far. I looked at as many
pictures as I could in the archives and in books. From what I
have seen there are tons of different aiptasia "types"
and couldn't find the exact picture of mine.
<<The photo provided is not really close enough or sharp
enough for me to tell for sure. These 'could' be Aiptasia
but I don't think so. They could also be Anemonia Majano, or
a Hydroid; which some folks consider to be a worse scourge than
Aiptasia (try some keyword searches on those names and see what
you think). But to me, these polyps look to be Scleractinian
rather than Actinarian (hard corals vs. anemones/similar animals)
as it appears there is a 'skeletal structure' surrounding
each (or maybe it's just the photo). I'll ask Bob to
comment re if he sees this>>
<Mmm, is a Scleractinian... perhaps solitary Caryophylliid...
I'd leave alone.RMF>
I was sort of hoping it would be something else like possibly
some sort of worm?
<<Not a worm'¦but quite possibly a
I fear I am wrong though and wanted an expert opinion.
<<I can't be sure without a better resolved close-up
I thought I had taken precautions against these pests.
<<These may not be the 'pest' you
fear'¦though it is essentially impossible to keep
Aiptasia from eventually showing up in a system, in my opinion.
Best to be vigilant'¦and to have a plan>>
I have 3 peppermint shrimp, and some red legged hermits,
apparently mine don't eat these so hopefully it will be
<<I have always found such 'biological controls'
for Aiptasia to be unreliable and of little use. For
Aiptasia/pest anemone control I very much recommend the use of
Red Sea's Aiptasia-X>>
I have read emerald crabs eat these too.
<<Not in my experience>>
Maybe I'll be buying one of those?
<<The money will be better spent on the
I planned on changing my CC substrate to a DSB in the morning but
now am unsure of what to do. I read a lot of posts where people
get these epidemics and can't seem to get rid of them.
<<Based on the photo, you hardly have an
Should I remove the rock and let everything die off and never buy
rock from this LFS again?
<<Mmm, no'¦a bit drastic and unnecessary in my
Please tell me it isn't aiptasia.
<<Can't say for sure. Get a bottle of the Aiptasia-X
and if they continue to spread or if it just makes you feel
better, you can get rid of them. Otherwise, I would be inclined
to watch/enjoy them for a while and see what develops>>
Thank you very much for your time and help.
I don't have any friends in this hobby yet and don't
trust the guys at my LFS after selling me the CC substrate and
now this ugh.
<<The local fish stores (or anyone for that matter)
don't always have all the right answers or provide the
'best' advice'¦and don't forget they also
need to make a buck. Some stores are certainly better than
others, but regardless of which is available to you; do your
research ahead of time and learn to rely upon yourself and your
own good judgment>>
Nitrate And Unidentified Invertebrate
The picture isn't Jordan's award :>
I have two questions, I have a 65 gallon saltwater tank with soft
corals and fish. I've had it for about 14 months and really
enjoy it, although it is a continuous learning process. Water is
changed weekly, calcium, strontium, and iodine was added and
everything has been fine except I can't get my nitrate lower
<How about magnesium levels, is a major element.>
I've done multiple water changes, watch how I feed and
everything is healthy in the tank. Is 20 an acceptable level?
<If your kit measures NO3-N, 20ppm would be acceptable for
fish only systems, but for corals, your measured level is
Are you using a protein skimmer? This will aid immensely in
lowering nitrate levels and is considered a must have for
maintaining healthy systems.>
I've also got a new addition that must have come from the
rock. Can you help identify it, I just want to make sure it
isn't a glass anemone. The body is round with what looks like
the mouth in the centre, the tentacles are long and fine like
<Picture is a little blurry but from what I can determine, it
appears to be the dreaded aiptasia anemone. This needs to go.
Do search our site for info regarding this unwanted
Thank you for your help.
<You're welcome. James (Salty Dog)>
Coral ID 3/9/09
Hi there ladies and gents!!
As always, thanks so much for the great site and all the info. I
don't know what I would do without you guys sometimes!
Like now. I could really use some help! I recently bought a
critter pack, and need some ID help.
<? and ??>
I feel I need to give you a little bit of back-story, so you
don't think you're dealing with an idiot buying mystery
critters from random dudes. The owner of the company I bought
from was very accommodating, letting me know he could adjust the
critter pack to my needs. I told him what I have currently, so he
could use his judgment on what would be most beneficial for me.
He told me he was putting together something he thought would
suit my tank, and that he'd email me what he was sending when
he sent it. Which he did not do. And still has not done. The sale
went great, but for the last 3 weeks I have not been able to get
a response from him.?
Most of what I got was part of the original pack, I know what
I'm dealing with.?There were some mystery stars which your
wonderful site has helped me ID (Asterina).?But he included
2?coral frags that I'm clueless about.?I have searched
through your site and through what feels like ALL of the
internet, trying to find pics of them. I'm sorry to have to
bother you guys, I know you must get about a billion ID requests.
Although they seem to be doing fine,? I'm worried that since
I have no idea what they are, I'm going to kill them because
I'm somehow not caring for them properly.?I don't know
what kind of lighting, food, flow, etc. that they need.
<Like the Judea-Christian book of mythos and other similar
works, best to start off with naming, descriptive terms in
? Let me start off apologizing for the blurry pics. I spent 20
minutes taking shots and that's the best I could get. My
camera is apparently not as good as I thought!! Maybe a
description in conjunction with my blurry pics will help.
? The pink polyps, I think they might be star polyps?
<You do have some Clavulariids here>
I've seen pics that are close, but nothing that looks exactly
Some of them have 7 arms,? most of them have 8. They have what
looks like bumps on the ends of the arms, that are colored
<Yes... GSPs for short>
Not sure if they are actually bumps, or if it just looks like it
due to the color difference. The reason I'm not sure about
the star polyp thing is because they are not feathery at all. The
arms are very tube like. And they don't seem to be as long as
in most of the pictures I've seen.
? The white fragment. This thing is crazy. I had to put a shade
over it to take it's picture because the skeleton is so white
it just kept coming out a big white blob in the pics. Very white
skeleton, with very large nodes.
The polyps that come out of it are lime/fluorescent green. The
only pics I have found that look similar to them are sun corals,
but even those aren't right. Especially the colors.
<I do think you're on the right track here... There
appears to be a Dendrophylliid in your mix of images>
? Both of these retract at night and come out in the day. They
retract when touched, but do so slowly.?To get a size idea, both
of the fragments are roughly?2 inches square. Maybe an inch &
? Thanks so much for your time!?I appreciate anything you can
tell me to get me pointed in the right direction to find info on
these things. Have a great day!
<Vic... you'd do well to either "check out" a
coral book (Borneman, Calfo, Sprung, Fossa & Nilsen...) from
a library... or pick up copies for your personal use. Bob
Creature ID 3/5/09
Let me begin by congratulating you on a phenomenal website.
I'm just starting off in the world of marine fish keeping and
your resources and advice are peerless. Thank you.
I have a hitchhiker on one of my pieces of Live Rock and I've
searched your site and most other places on the web, but
can't find anything that resembles it. The organism
doesn't look anything like the images of Aiptasia or Anemonia
majano that I could find, nor does it look like anything else
that I've seen. Any help in IDing the creature would be
greatly appreciated. The centres of the organisms are a much
brighter green that what shows up in the images. The tentacles
retract very quickly into the body when disturbed and the
organism seems to be flourishing and growing rather quickly in my
otherwise barren tank (It's still just cycling with LS and
<What you have is a small Zoanthid colony. Read here and
Thank you again for your tireless efforts.
<Again, you're welcome. James (Salty Dog)>
Coral ID help 2/18/09
<Hi Gabriel, Minh at your service.>
Hello crew. Just need a little help with a coral I can't
identify. I got this piece from my LFS when I purchased a few
other things and they put this in there by mistake. I've been
doing a lot of reading and looking at pictures and still
can't figure out what this type of coral is. It has been in
my tank for over a few months and seems to be receding. The
branches on it where longer and more defined at one time. This
coral glows bright fluorescent green under actinic lighting. Any
help you could give me in identifying this coral so I can
research how to better care for it would be a great help.
<Based on the picture you've sent, it appears to be a
Nephtheid. If you browse through this page, you can identify
which genus it best resembled when it was healthy:
http://www.wetwebmedia.com/nephtheids.htm. Care and
husbandry information is available in those pages as
<You're welcome. Cheers, Minh Huynh.>