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FAQs on Identification of Stinging-Celled Animals 32

Related Articles: Cnidarians, Water Flow, How Much is Enough,

Related FAQs: Cnidarian IDs 1, Cnidarian IDs 2, Cnidarian IDs 3, Cnidarians ID 4, Cnidarians ID 5, Cnidarians ID 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 17, Cnidarian ID 18, Cnidarian ID 19, Cnidarian ID 20, Cnidarian ID 21, Cnidarian ID 22, Cnidarian ID 23, Cnidarian ID 24, Cnidarian ID 25, Cnidarian ID 26, Cnidarian ID 27,  Cnidarian ID 28, Cnidarian ID 29, Cnidarian ID 30, Cnidarian ID 31, Cnidarian ID 33, Cnidarian ID 34, Cnidarian ID 35, & Anemone ID 1, Aiptasia ID 1, Stony Coral ID 1, Mushroom Identification, Soft Coral ID, Alcyoniid ID, Xeniid ID, Cnidarians 1, Cnidarians 2, Cnidarian Behavior, Cnidarian Compatibility, Cnidarian Selection, Cnidarian Systems, Cnidarian Feeding, Cnidarian Disease, Cnidarian Reproduction, Acclimating Symbiotic Reef Invertebrates to Captive Lighting,


Identification anemone or coral. Neither     7/4/14
I found this colony in my live rock that is currently expanding. I believe these guys have a good punch because my Hawaiian dwarf eel got stung by one (even though he got stung by my open face brain coral). It has clear tentacles and an orange base. Enclosed are some pics and i do apologize because its hard to get a close up pic. Thank you.
<Mmm; yes. Pseudocorynactis... a Corallimorpharian. Bob Fenner>

Re: Identification anemone or coral     7/4/14
Thank you very much. That's definitely it.
<Ah welcome. BobF>

Identification!      5/20/14
Hi, I have an extremely established 30 gal reef tank and I just noticed this little guy today. I have no idea what it is! I barely touched the side of it with my fingernail and it shrunk up like an anemone would.
<Neat! An Octocorallian of some sort. See here:
and direct yourself along the stated listings to the group it belongs>
It's the only one I can spot at the moment. It's so small, sorry if the picture is a little unclear.
I was also wondering if it is a pest.
<Not likely>
Thanks y'all! :)
<Welcome. Bob Fenner>

critter Identifications      4/1/14
I have recently resurrected my reef tank (about 6 months). So far it appears that things are going pretty well as I have started seeing evidence of new life forms including macro algaes, small brittle stars etc.
However, I am having some difficulty identifying some of these new creatures. The first of these are documented in the attached photos.
These creatures are actually quite small (1/8" - 3/16" dia) and they are extending from some small tube like structures that appear to be similar to coralline algae.
<I see these in your pix... Polypoid, retractile. Perhaps a Hydropolyp of some sort>

After re-arranging some of the rock in my tank I found another life form that I would like to identify. It is a small clear, transparent tentacled creature about the diameter of a nickel. The tentacles are about an inch long, tapered and have small white spots on them with a larger white spot  on the tip of each tentacle. Unfortunately due to the transparency of this critter I couldn't get any photos.
<Likewise probably a Hydrozoan>
Aside from my basic curiosity and desire to learn more, I also want to ensure that I don't have some type of species in my tank that could cause problems.
<These sorts of life forms come and go of their own accord in captive  systems. I wouldn't over-react>
Since I have resurrected this tank, I have purchased livestock from only one store. Ironically, I have never seen any of these life forms in their tanks so I don't know where they came from. It is almost like  these things are just appearing with no explanation. Is this just normal biologic growth as the system starts to mature? Any help you can provide will be greatly appreciated.
Eric Wilcox
<And you, Bob Fenner, Cozumel>

Identifying Brown Tube Worms    3/3/14
My reef tank is being taken over by what looks like tiny brown tube worms and I'm at a loss for what they might be.  They are becoming quite the nuisance.  Here are some characteristics:
<I'll bet...>
·         Feather "heads" retract when touched.
·         Tubes are flexible but don't easily bend.
·         Length is about 1/4 inch
I don't know if these are tube worms or something different,
<The latter; they're Cnidarians...>
but I'd like to ID them to determine if they are could be stinging or irritating my corals.  I've attached some pictures to help ID these little critters.  I've scoured the web, including your site, but haven't found anything to concretely ID them.  I did find one picture that looks like these on another site, but no conclusion was drawn on what they are.
Please let me know if you need any other information.
<Either Aiptasiids, or possibly Zoanthids... NEED to be confined, cropped back, isolated on single rocks. See/read on WWM re. Bob Fenner>

Odd flower like object on live rock, green and very tiny   2/1/14
I found the attached object on my live rock recently and cant figure out what it is, even after hours of Google searching, including your site!
<Mmm, looks Polypoid... My guess is on some sort of Hydrozoan... Does it "sting", stick to a sensitive part of your wrist? Yowch!>
The live rock I bought only stated that it is usually from the South Pacific but could be from anywhere.
The object is ridiculously small, maybe 1/4" high and a few mm wide. It doesn't come off the rock with a baster like algae (I do have diatoms and GHA). I originally thought it was a new strand of algae.
I have asked over at Nano-reef forums but the only idea I got was that it could be some sort of macroalgae. This tank has only been up for about 6 weeks and currently only has live rock in it.
I have only noticed this one in the tank and it's stationary, I haven't noticed if it looks any differently at night than during the day. My apologies that the pictures aren't better.
<Welcome! Thanks for sharing. Bob Fenner>

Re: Odd flower like object on live rock, green and very tiny   2/1/14
Thanks Bob, I've never touched it so not sure if it stings! I'll see if I can trick my boyfriend into finding out...
<Heeee! Good idea... the wrist, not callused hands or fingers. BobF>

ID of the attached creature     1/11/14
Can you please ID the creature as shown in the attached photo?
I have spotted it in my aquarium.
Aquarium data:
10 gallon reef
Salinity: 1025
Temp: 26 C
pH : 8.1
KH : 11
Ca : 420
Thank you!
<A Cnidarian for sure; possibly a Telestacean. Bob Fenner>

Stony coral hitchhiker   11/2/13
I have what I thought was two pest Mojano anemone  and now a third has shown up all within two inches of each other. I know it's not a Mojano  because when I touch it, it retracts into its skeleton. They are very small only 1/8" in diameter and they resemble a plate coral. I have not had a plate coral in this tank or any of my other tanks, the rock was dry rock with no skeletons on it. Any info would be helpful.
Thank you
<Very likely Corallimorpharian/s... see WWM re. Bob Fenner>

Strange Creature ID?   9/14/13
Hello all,
<... six and a half megs of pix. What are our requirements?>
I have a strange creature that I would like some help identifying. There are many of them (over 50 that I can guess) in my 29 gallon BioCube reef.
It is semi-transparent to opaque-white worm like creature. They are slender (~1/32"-1/64" diameter when stretched) and long (1-3" long) when fully extended. It seems as though there are adult versions and newer smaller versions. They are fixed on a hard surface at their base end and they don't travel from those fixed points. They are found on my live rocks as well as in between my Zoas and Green Star Polyps. They have fuzzy or furry looking appendages all over their length. Their 'head' is almost Q-tip shaped when fully extended.  They extend in the flow of the currents but can somewhat control their direction of movement if the flow is slow enough. However, they are only extended in low light or at night. They will retract and withdraw back into their 'base' in 3 or 4 jerky movements within a second or two when a flash light is pointed at them. During the day, they are nowhere to be seen except for the ones attached in dark shaded areas only. At first, they don't seem to affect anything. They don't affect my soft corals (Hammer, Frogspawn, Duncan, Leathers, Ricordeas etc. However, I started to notice that some areas of some of my hard corals (Acroporas) were 'bleaching'. After the 'bleaching', that area began to die off and turn to base skeleton. Upon further examination at night, I noticed that these unidentified worm-like creatures were constantly touching the corals on and off. Those areas that were being touched were bleaching and dying off. I then scraped the base where a few of these worms (near the Acroporas) where extending from to try and remove them and noticed that for the next few nights the worm-like thing was no longer there and within a few weeks the coral began to heal and regrow in that area.
Taking pictures at night was very difficult and I couldn't get anything worth sending as they are so thin and almost transparent looking as well as constantly moving in the current. However, I removed a Zoa plug that happened to have one of these 'creatures' and dipped it in Coral Revive for a few minutes. The Coral Revive appears to kill the 'creature' so I scraped it of the frag plug and was able to take a picture of it. For reference sake, the base of the black container is ~2" across.
Any help with ID'ing this would be greatly appreciated. Thanking you in advance.
<Mmm, my best guess is that these are Pennatulaceans. Bob Fenner>

Re Strange Creature ID?    9/15/13
Lynn, what do you think? Pennatulacean? B
Re: Strange Creature ID?    9/15/13

Lynn, what do you think? Pennatulacean? B
<That would be my guess as well.  Here's a link with some examples for
Take . Take care,  Lynn>
<<Thank you Lynn. B>>
Re: Strange Creature ID?    9/15/13

Hello Bob,
I sincerely apologize for the previous large sized attachments... I had no idea that they were over 6 megs.
I've attached 2 much smaller sized pics for you to view.
My other questions that I forgot to ask are:
a) are they as harmful as I think? and if so
b) is there any way to remove them other than by physical means? I notice that none of my clean up crew or shrimp touches them.
<Likely not very harmful, though are Cnidarians... and very likely will just "go"; pass on their own. I would not make extraordinary action to eliminate nor remove them>
Thank you for taking the time to view the pics and answer my questions.
<Ah, welcome. BobF>

Re: Strange Creature ID? Penn...    9/16/13
Thank you very much for your prompt reply! I greatly appreciate all your help.
Have a great day!
<Ah welcome. You as well Nick. B>

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