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FAQs about Marine Worms, Vermiform Animals Identification 20

Related FAQs: Worm IDs 1, Worm IDs 2, Worm IDs 3, Worm IDs 4, Worm IDs 5, Worm IDs 6, Worm IDs 7, Worm IDs 8, Worm IDs 9, Worm IDs 10, Worm ID 11, Worm ID 12, Worm ID 13, Worm ID 14, Worm ID 15, Worm ID 16, Worm ID 17, Worm ID 18, Worm ID 19, Worm ID 21, Worm ID 22, Worm ID 23, See Also: Flatworm ID 1 +, Nemertean, Proboscis, Ribbon Worm ID 1, Nematode, Roundworm ID 1, Nematomorpha, Horsehair Worm ID 1, Acanthocephalans, Thorny-headed Worm ID 1, Tubeworm/Featherduster ID 1 +, Bristle Worm ID 1 +, Hirudineans, Leech ID 1, Sipunculids, Peanut Worm ID 1, Echiuran Worm ID 1, Invertebrate Identification, Worms 1, Worms 2, Worms 3, Flatworms/Planaria, Fire/Bristleworms, FAQs on: Worm Behavior, Worm Compatibility, Worm Selection, Worm Systems, Worm Feeding, Worm Disease, Worm Reproduction,

Related Articles: Worms, Featherduster Worms,

Id of worm/potential young sea cucumber      6/13/18
Got a frag of sps of a fellow reefer and found a couple of worm like creatures that are very small on the bottom.
The guy i got the frags from has 2 cucumbers in his tank. To the best of his knowledge no bobbit/eunice worms.
Wondering if you might be able to id or help out.
The large one in pictures is about 4mm long.
<Wow! No wonder your pix aren't cropped, crisp (highly resolved)... Likely are Holothurians, but could be some type of worm. I wouldn't panic. Thanks for sharing. Bob Fenner>

Re: Id of worm/potential young sea cucumber      6/13/18
Hi Bob,
Yes was very hard to get pics. Those were the best i could get.
So you would say safe to let loose in display?
<Yes; I would>
I figure if they are small holothurians the sand would be a benefit.
<Agreed. Cheers Adam. BobF>

Flatworm or something else?       4/11/18
Hi WWM Crew,
Was hoping to get an ID on the mysterious creatures in the attached photos.
<Appear to be Acoel flatworms... Likely no big deal. See WWM re>
Thanks for your help!
Adam Clayton
<Welcome. Bob Fenner>


Unknown worm.      7/10/16
After a couple of years of happy reefing and not bothering you guys. I added a new rock to my tank. And a couple of days later I noticed a worm in my tank. Looked all over your site and haven't found one that matches.
About 2 foot long and about 1/4 inc in circumference. It has legs like a centipede but they seem to point up and down. About every third one or so is sticking up. The head end looks like a worm with a square shovel for a head. I tried taking a picture but it sucked. I found one online accept that I didn't see eyes on mine, but the shovel shaped extension is similar. Mine might have been a bit more squared and thicker. I have seen it a couple of weeks but I haven/t realized how big it was until it has migrated earlier this week and it seemed to go on forever. But judging on where the head was and the tail was its about 2 feet maybe more. It wasn't a concern until I saw it bug my turbo snail earlier today. It didn't seen to have taken a bite just poked it with the head end an than gave up after several attempts. I attached a couple of pictures and a video. Hopefully it will all fit in your inbox. Please let me know what you think it is and if I should try and get it out. And if I do, should I wear some sort of protection. Thank you. Artur.
<Hi Artur
Jordan with you tonight. Unfortunately you have an Oenone fulgida. A particularly nasty predator that I'm all too familiar with. They prey primarily on gastropods but I've seen them go after other inverts. They are primarily nocturnal and it is odd that you saw one during the day. I would take that as a sign that there are likely many more. I've had success removing them with a PVC trap. Use an 8 or 9 inch piece of PVC capped with removable ends. Drill a small hole in the pipe for the worms to enter. Bait the trap using PE Mysid inside a mesh bag that is tied shut so they cannot get to the bait. Place in the tank at lights out and pull in the morning.
Wear gloves as the worms produce a toxic mucus. Conus regius can be used to keep numbers in check but it will prey on beneficial Polychaetes as well.>

White growths on LR       4/14/15
Hey Bob, I just finished cycling my 55g QT with LR. After almost 2 weeks all readings are at 0. My wife noticed these little white fuzzy things growing all over the rock. It kind of resembles lymph in some spots. What do you think, worms? sponges? Is this normal?
<Small tubiculous worms; likely Serpulids>

Re: In need of an ID      2/19/15
<Mmm; thank you for providing the MOV... this is a worm of some sort...
will have to check when am not so tired.
Bob Fenner>
Re: In need of an ID      2/
<Though it should be "in the substrate" the movement and oral appendages of this animal remind me of a Sipunculid, a Peanut Worm. Bob Fenner>


ID help       1/30/15
Can you help me ID this please
Your help is greatly appreciated
Katie Bramlett
<Appears to be a Sipunculid; a peanut worm; though it might be an Echiuran. Bob Fenner>

Unidentifiable Worm      1/21/15
Good afternoon everyone :)
<Bri; ten megs of pix; really? They're too poor in quality, not cropped... >
The other week when I was feeding my tank, I noticed an almost clear worm coming from out of my rock. It looked like it was a feeding off of the rock.
<I see this in your .mov>
The mouth and body was shaped like the detachable end of the vacuum hose, the circular mouth of it.
I've Googled and Googled and Googled trying to figure it out, but no luck :( thank you for any info that you may be able to help me with
<Looks more like a small Holothuroidean to me than any worm-group. Bob Fenner>

Re: Unidentifiable Worm      1/21/15
Thank you for your fast response Mr. Fenner:) I apologize for the picture quality, as I took them and sent them through my iPhone and didn't realize that it would be difficult to see. Once again thank you kindly, and I will be Googling about these now lol. If I may have any other questions regarding this, am I able to reply to this email?
<Ah yes. Cheers, BobF>

what is this creature?      12/2/14
i found a flatworm i removed it from the tank, then i looked at the same spot the flat worm was (on Zoas) and there was something else i removed it from the tank and took these 2 pix of it. the front and back of the creature, it was moving almost looked like it was walking using the spikes, look like it had a mouth or anus on the flat side edge where there are no spikes.
<Yes; I agree; and a good clue>
it was about 2-3 cm in length, it was flat, slimy, no segments, i have shown the pix every reef store in the phx az area and i have show it to a Facebook marine society, i have spent countless hours Googling everything from bristleworms to Nudibranchs, to cucumbers to flatworms. i cant figure out what this creature is.. can you tell me? sincerely Jill
<I do think this is an Errantiate Polychaete... a reproductive part... epitoke.... The bristles/chaetae are definitive... Still, this is only a guess. Thank you for sharing. Bob Fenner>

What is this?      11/7/14
<Mmm; bigger than a bread box, smaller than Yugoslavia? Looks like a worm of some sort, or a seed... Need more definition. Bob Fenner>


What is it       11/7/14
<.... a worm... See here: http://wetwebmedia.com/wormidfaqs.htm
and the linked files above. BobF


Strange Alien-Like Worm Identification. Shades of F. Herbert's Dune!     10/9/14
So I found the most bizarre animal in my marine tank today. I am pretty sure it is a worm because it had at least part of its tubular body stretching over the top of a rock in a crack, biting at something. It was black for the most part, with a small slender body that looked only about as thick as the pencil lead on an No. 2 pencil. It seemed to have a few non-distinct white vertical stripes going from head (?) to whatever was on the other side of that rock. The crazy part was its mouth. I have seen some species of worms that have this mouth, though I think I saw them on “Monsters Inside Me." Its mouth just looks like a black rounded nub when the inside of it isn’t detracted. When it would move toward whatever it was it was eating (something a spaghetti worm was munching on or the spaghetti worm itself) the inside of its mouth would come out like some alien creature. It was crowned- like a round array of white teeth or something. It would stretch these out, lock on to food, and pull it back into its mouth/body. This was crazy to watch. You could tell when it would finally yank hard enough at its food, because it would move back quickly. Another really strange thing about this worm is that it was responsive to my movement outside of the tank. The second time I walked up on it, I scared it at a few feet away from the tank and it went behind the rock halfway, then I moved my arm a little bit more and it hid completely- with fast reflexes. This was during the day.
So, do you have any idea what this may be, and is it safe for my tank?? I’m sorry I couldn’t get any pictures. I’ll see if I can get a decent-enough one.
Thank you!
- Lexi
<Do have a look/see over the WWM "Worm ID FAQs files"... Start here: http://wetwebmedia.com/WormID18.htm
and the linked files above. Bob Fenner>
Re: Strange Alien-Like Worm Identification     10/9/14

I have already looked over the worm id's, every worm that was black and white was not the same as the one I saw!
Re: Strange Alien-Like Worm Identification     10/9/14

I know it isn't much but I got a picture! It's the diagonal-ish like in the center of the photo. It seems to have a grey belly
<... need a better pic>


Re: Strange Alien-Like Worm Identification     10/9/14
I got some better pics. It's skittish so I have to sneak up on it on all fours.. Haha.
In the second picture you can barely see it's teeth.
<Still need a better head shot. B>


White Worm... tiny, blurry ID     3/18/14
I've been referred by Tomgl of Las Vegas Marine Aquarium Society to ask you about the identification of this worm I found in my tank since they are also not sure what it is. I have already searched the internet on what kind of worms these are but most answers are guesses. And even though there was no specific answer most of them say it's a good worm. Thanks in advance and more power to you and your crew.
<... need a better pic... more resolution. You're free to scan the several worm/group ID FAQs pages of WWM for more.
Bob Fenner>


snails, crabs and HITCH HIKERS!     1/31/14
Hi Crew!
I just ordered a ton of snails and crabs to help with the sifting of my deep sand bed, as it has formed a crust,  and when I siphoned it during a water change, the smell was WORSE that my skimmer! That's bad!
I'm hoping this is "the ticket" to a healthier dsb!
<Yes; do read our/my input re DSB maint.... Includes periodic (weekly) stirring, vacuuming of at least part/half>
I've attached a picture and I know it's a bit blurry, but there's a little hitch hiker on one of the Turbo snails.
It's amber in color and about a half inch in size. Would this be a feather duster? It's very sweet :)
<Ah yes; and yes>
Thanks for the help/ advice as always!
<Only state what I might do given similar (stated) circumstances. BobF> 


need help identifying worm   1/22/14
Hi Crew!
First, love the site, really helps a lot! Second, I've Google searched this so much and I still can find one that i think looks like the pictures. Its in with my copepods in the mess they make, very small, but visible to the eye. Brown in color, same as the copepods waste. I could not see with visible eye that they had tiny leg like things.
<Yes; podia, parapodia...>
 Under scope they do and a round head with interesting dark spot that i don't think is eye spots and two points at the back of it.  I just want to make sure they aren't eating my pods, i think they're harmless just bottom tank cleaners but I'd like a second opinion. I have not noticed a decrease in pod population but these things are increasing in population.
<Epitoke phase... Errantiate Polychaete ("Bristleworm). Bob Fenner>

Re: need help identifying worm   1/22/14
I Google searched the Errantiate Polychaete and looked at your site, i got this from your site...
"Errantiate Question  9/28/05 Hello,
<JackDan> I have a Marine Tank.  I identified these worms in my tank as  "Errantiate" through your site.
<Ah... yes... a "higher taxonomic" category of Polychaete worms... Sedentariate ones are tubiculous... make tubes, don't
move... Errantiate ones, as in "to err is human" (sort of) are mobile... they move about>   Now that I have
identified them, I'm having trouble finding out if they are good or not. <Most are no problem. Larger ones, or too many
can become predaceous> "
if it gets big then I could have a problem...  Since its so small I'm assuming this one will not get huge and hurt things... Or could i be very off and this thing could get pretty big? I will keep them separate and watch them grow i guess to see how big they get.
<... can't tell "at this juncture": but I would not be concerned... There are many species; large and small... but most won't/don't survive metamorphosis/es in captivity. Likely "these too shall pass">
Will this guy be bad for my pods or my tank? Or is he just a scavenger that will help clean things up? Don't want a predator if i can avoid it.
<A distant possibility of concern. Again, don't panic. BobF>

Coral Killing Worm??   12/23/13
<Steph; you're about an order of magnitude over our stated file size>
This worm type thing has just made itself visible over the last couple days. Not quite sure what it is and just so happens to be wrapped around in the trumpet colony (about 15+ heads) that very suddenly began dying and are dying very quickly....very close to being 100% dead now. It looks like it was eaten down to the skeleton! At least it does to me....
<Mmm, not from this organism>
Any clue what this thing is?? It is about the thickness of a strand of hair and tan & black striped and quite long...about 3-4 inches so far. My leather coral which was a neighbor of the trumpets is nearly on its side today and I am wondering if this thing started to mess with it. Don't want to go sticking my hands in there to get the dead trumpets out without knowing this thing wont hurt me haha.
<Could be a type of (Sedentariate Polychaete) spaghetti worm... >

See attached pictures. Thanks kindly for your assistance & Happy Holidays!
<Thanks. Something else going on here... a lack of nutrient, allelopathy likely... Write back w/ the history of stocking, the gear employed (esp. chem. filtration), any water quality test results... Bob Fenner>

re: Coral Killing Worm??   12/24/13
Were you able to see the picture? Is it that the picture was too large or was it too many pics?
<... the total file size. See where you find how to write us if concerned>
My tank is a 29g biocube with a history of high nitrates :very high 80+ at times:
<I encourage you to read on WWM re ways/means of controlling NO3>
 and am FINALLY putting in a skimmer this wknd also my bulbs are probably just about 9 months old..also about to upgrade to LEDs finally.
My Favia frags died then my trumpets started going!
<... at least water quality to blame>
 My Ricordeas, mushrooms, softies & Zoas have been beautiful.
<... these last three poisoning the others when stressed. Read here:

and the linked files above... esp. for the Zoanthids, Alcyonaceans... One can keep such a mish mash together, even in small volumes, but the systems must be homeostatic (stable) AND optimized... Yours is not...>
The mushrooms are dividing like crazy.
I have a plate that is bigger than ever and looks good & another baby plate growing from a colony of Zoas. Pair of clowns, 6ish Astrea Turbo/Trochus Banded mixture with one or two Nassarius remaining.
My last hermit bit the dust as well (was 9 months old). The funny thing is that the hermit died right on the trumpet colony base close to where that worm is coming from. I also have some microbrittle stars, bristleworms, lots of feather dusters, colonial hydroids, etc hitchhikers. My 5ish month old Scooter Blenny also disappeared last week. Literally disappeared.
Still no sign of it.
Unsure what Allelopathy means. Battling some Cyano now. Things aren't going great in there. I had ignored it a bit because I was just getting ready to upgrade and was hoping once that occurred things would straighten out but cannot upgrade now as my significant other got laid off last week. So, for xmas i will be buying myself a used AquaticLife 115 & either the new bulbs or a retrofit LED kit. Also about 3 months into my Purigen & ChemiPure so about to switch those out. And im running a small fuge in the back.
Im getting ready to really overhaul this mess of a tank!
Incase you are able to view just one photo I have included one. I am not sure how to resize and such.
re: Coral Killing Worm?? Take 2    12/24/13

Sorry - forgot to add the photo. Also, I was using alot of Prime during the last week since the scooter blenny disappeared....incase he is decomposing in there!
<Not a viable method to resist pollution. B>
re: Coral Killing Worm?? Take 2    12/24/13

<Don't write: READ>
No? I thought it would help keep any possible ammonia from being toxic...aside from a couple extra water changes that is. So, I shouldn't use the Prime?
Does the worm look like a Spaghetti Worm to you? I know I have Googled them & they aren't usually striped like that? I apologize for my ignorance here.
Im excited to get things back on track. Slowly but surely.
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