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Bristle/Fireworms (Errantiate Polychaete) Identification FAQs 9

Related FAQs: Polychaete ID 1, Polychaete ID 2, Polychaete ID 3, Polychaete ID 4, Bristleworm ID 5, Bristleworm ID 6, Bristleworm ID 7, Bristleworm ID 8, Bristleworm ID 10, Bristleworm ID 11, & FAQs: Worm Diversity FAQs, FAQs 2, FAQs 3, & 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 ID FAQs by Group/Phylum: Flatworm Identification ID, Nemertean, Proboscis, Ribbon Worm ID, Nematode, Roundworm ID, Nematomorpha, Horsehair Worm ID, Acanthocephalans, Thorny-headed Worm ID, Tubeworm ID, Hirudineans, Leech ID, Sipunculids, Peanut Worm ID, Echiuran Worm ID, & Bristle/Fireworms 1, Bristle/Fireworms 2, Bristle/Fireworms 3, Bristle/Fireworms 4, Worm Identification, Polychaete Behavior, Polychaete Compatibility, Polychaete System, Polychaete Selection, Polychaete Feeding, Polychaete Disease, Polychaete Reproduction,

Related Articles: Worms, Polychaetes, Flatworms/Planaria,

Constructive worm 4/7/2011
<Hi there Carissa>
I have some kind of unusual worm that I can't find a similar description anywhere! I've only seen its head once for a few seconds just before turning off the lights as it appeared to be grazing on some algae-- a kind of grasshopper like head with short antennae. He seems sizable, the head was about 3/8 inch wide. So he could be a Bristleworm,
<Very likely so>
but this worm seems to have a talent of moving small rocks and attaching them to the rock he lives in (see attached picture-- his home rock is like a piece of Swiss cheese, so I can't find him during the day). The white rocks on the left side were brought up about 5 inches from the bottom of the aquarium just last night, and as a reference for size, the one at the front is about 3/4 inch long! They are very light weight aragonite, but I'm still thinking, how big is this worm to bring up these pieces of gravel?
<Good sized, strong>
Then the rocks are connected to the 'home rock' with strands of silk-like substance (seen in the middle section just under the red macro algae). And the pieces at the right are attached and hanging from the rock. The rocks aren't in any particular tube shape, either; just placed in-between the two rocks.
<A good clue. Perhaps this is a Eunicid... see the Net re>
I'm not too concerned about the worm harming anything else in the tank.
I'm just wondering what it is and if it will grow into a giant. I've had my tank for 2 months and the live rock with the worm for about a month.
Specs: 26 gallon saltwater, canister filter, skimmer, 76 degrees, ph 8.3, ammonia 0, nitrite 0, nitrate <5ppm, 2 green Chromis, 1 Firefish goby, frag of brown Zoas.
Thanks for any help!
<Could be trouble for the Firefish if this worm is hungry. Bob Fenner>

worm head?

Identify Worm: Eunicid -- 3/11/11
Hello Fish Deeva (love the name, by the way), Lynn here today.>
Any idea what kind of worm this is? I did look. I am praying it's not a giant reef worm.
<Nah, it's not a giant reef worm, it's an itty-bitty one! It appears to be a small Eunicid (Polychaete in the family Eunicidae) of some sort but most likely not the variety that gives hobbyists nightmares (Eunice aphroditois). Eunicids such as yours tend to prey on small pods and/or other worms/critters that stray a bit too close, but thankfully don't pose much threat to larger livestock. They also scavenge bits and pieces of food that land nearby. All in all they comprise part of the beneficial biodiversity that makes for a healthy system.>
If so, any idea on how to get him out?
<I'd leave it in place. Trying to grab one of these worms is next to impossible since they're able to retract into the rockwork at lightning speed. Trapping doesn't tend to work well either because they apparently don't like leaving the relative safety of their hole in the rock. I've seen individuals reach way out to scavenge, but I've never seen one completely leave its 'den' in order to forage/hunt. The only other alternative as far as removal is to take the rock out and either try to flush the area with freshwater (which would kill everything on that part of the rock (= potential ammonia spike), or try sealing the hole that the worm retracts back into with a gel-type superglue used for gluing frags. The problem with this last option is that many times, these worms have multiple entrances/exits. If it were me, I'd just leave the little fellow in place and enjoy watching him. For more information/list of related FAQ's, please enter the term 'Eunice worm' in our Google search engine: http://www.wetwebmedia.com/Googlesearch.htm >
<Neat video, thanks!>
Fish Deeva
<Take care, Lynn Z>

Worm ID: Syllid within Palythoa Colony -- 3/9/11
Hey WWM Crew,
<Hey Todd, Lynn here today.>
I found this little critter on my Palythoas and was wondering if you knew what this worm is?
<Yep, it's a type of Syllid, most likely in the genus Myrianida, that's in a reproductive phase. Syllids are generally fairly small worms (couple of cm/<1'), that tend to live either in the upper layers of the sandbed or above it, where they're associated with everything from sponges to corals, tunicates, hydroids, bryozoans, etc. It's a very diverse group of worms.>
I am not sure if it was eating my Palythoas, but it was for sure irritating them.
<I bet so. The last time I ran across one of these guys, it was associated with Palythoas and was indeed either consuming, or at the very least irritating them. I would remove this, and any others that appear within the colony. For more information, please see the FAQ titled 'Saltwater Polychaete ID Question: Syllid Stolonization -- 1/19/09' at the following link (as well as link supplied within): http://www.wetwebmedia.com/PolychaeteIDF7.htm?h= >
My best guess would be that it is in the Class: Polychaeta, but I am not positive.
<Right you are. It's a Polychaete in the family Syllidae.>
Any insight would be greatly appreciated.
<You're very welcome.>
<Take care, Lynn Z>

worm? 3/1/11
Hey guys! Might be a rhetorical question and if it is, I'm sorry. I attached a picture of what I think is a spaghetti worm...?? If so, I've read on your site that they're good to have and I have maybe 1000 in my 46 gallon tank that is just housing them along with seasoned live sand...... moved everything else to a 150.
Thanks for the info ahead of time!
<Does appear to be part of the cephalic end of a Terebellid. Bob Fenner>

Strange worm? 2/13/11
Hello Bob and crew.
After feeding my reef tank tonight, I noticed a strange creature I am hoping you can identify for me.
At first I thought it was a very fast, small red fish...but it seems to be some sort of worm.
It is probably about 2 inches long. The 'head' of it is white or light grey and the body is red. It is rather fuzzy, especially the head area. It wriggles it's body to swim, and looks like a fish swimming very fast all over the tank.
It has what actually look like fish eyeballs, and darts to the surface to grab food. It knows exactly what it is doing -- darting to the surface to grab food, then swimming to more food or to shelter, then back to grab more food.
My Randolph's <?> Damsel seems to be a bit afraid of it.
Any idea what it could be or most importantly if it could be harmful?
< Who knows?>
I couldn't possibly get a photo of it due to it's speed -- it actually hurt my eyes to follow it darting around the tank.
The tank is 55 gallons, around 65 lbs live rock, all parameters are in 'normal' range.
Thank you!
<Likely an epitoke... See the Net re Errantiate Polychaetes. Bob Fenner>
Strange worm? Email 2 2/13/11
Hello again. I think I was finally able to find out what the worm in question is. It appears to be an Epitoke?
<Oh, likely so>
The lights are out on the tank right now and I can still see it swimming around like crazy under the moonlight.
Almost the craziest thing I've ever seen in my tank -- the craziest being the corpse of what I think was some sort of yellow Blenny swirling around in the filter currant, which I had never seen before and must have been living in there unnoticed for a good couple years....
<Mmm, no; not as an epitoke>
he sure was a cute little fish and I was so sad he was dead...I actually thought he was a large leaf swirling around in there until I saw eyeballs.
Hopefully I was able to identify this Epitoke creature correctly, since they are apparently harmless.
Thank you Bob and crew....for all the personal help and the great website.
<... welcome! B>

Nudibranch? -- 02/04/11
Hey guys! As always, you guys rock!
<And roll!>
I need some help identifying a Nudibranch/worm/slug... I've never seen this one before. Any ideas?
<Looks to be an Aphroditid: http://en.wikipedia.org/wiki/Sea_mouse>
John Patten
Tampa Reef Marine Management Services, LLC
<Welcome! Bob Fenner>

Re: Nudibranch? -- 02/04/11
Should I discard it? I found it in a Nano reef.
Thanks again!
<... depends on what you have, what you're trying to do w/ "it"... See the Net re the life habits of this Errantiate Polychaete family. B><<Don't tell John... but mainly this family consumes other worms... Nereids principally, Shhhh>>

Mysterious Worm: Cirratulid/Hair Worm -- 1/15/11
Hey WWM Crew,
<Hey there, Lynn here today.>
I am currently stationed overseas in Japan and decided to start a saltwater aquarium
...and recently I found this mysterious worm in my 30 gallon tank. I noticed it when I was cleaning out some of the sand because I noticed a red algae growing under the sand along the glass.
<Sounds like BGA/Blue Green Algae/Cyanobacteria. Please see the following link (as well as related links at the top of the page) for more information: http://www.wetwebmedia.com/bluegralgae.htm >
When I went to pick up my live rock I noticed two reddish thready balls hanging onto the bottom of it. I set my live rock in quarantine and noticed that the balls were moving. After about 5 minutes one unraveled to reveal a 3-4 in thread like worm. This worm seems not to have a solid body but tiny threads and tentacles. I have done some research but still can't find anything on them. Can you help?
<Yep, no worries; you appear to have several harmless Cirratulids (aka 'Hair Worms'). Most are 2" or less in body length but the various appendages (two long feeding tentacles and a number of filament-like gills can add to the appearance of overall length. Please see the FAQ titled 'Red Stringy Creature: Likely Cirratulid -- 10/14/09 at the following link for more information: http://www.wetwebmedia.com/nonvertIDF49.htm?h= >
Thank you
<You're very welcome. Take care, Lynn Z><<Ahhh!>>

Sand tentacles.. 11/4/10
<Hi Gregory>
Thanks so much for all your help. WWM is amazing and I enjoy reading your responses.
<Thank you>
I was hoping for some identification help. I have had a 90 gallon aquarium up and running for several years. From time to time later in the evening when my lights transition from MH to only T5's and on into
night time, I will see clear almost transparent tentacles emerging from the sand. I do have a DSB of 5" to 7", I don't know why but I first thought Aiptasia, but I don't think I'm on the right track (its seems to not like the light).
<This is difficult to see, but could easily be Aiptasia, and would be my guess>
Recently, I was able to get a photo of one that is next to the glass (attached). I hope you can see the distance the tentacles are extending. Sometimes the base or trunk extends higher than the turbo shell in the background.
Thanks again!!
<No problem>
Greg C.

Re: Sand tentacles.. worm 11/10/10
Hey crew!
<Hey Gregory, sorry it has taken a few days. Am snowed under at the moment and will be out for a while>
Leave it up to the wife, she found out what my the sand tentacles were.
They are Polychaete worms.
<Really? Did not look like it to me, but ok>
Terebellid is what she is saying, but uuhhh after confirming what she found out, I found a perfect example at http://www.wetwebmedia.com/WormIDF15.htm
titled "**Identification Weird tentacle sand worm" Are these guys anything to worry about?
<Nah. Are beneficial life forms, contributing to the plankton in your system, and the clear-up of detritus>
I seem to have quite a bit of them.
<Will 'wax and wane' with your system, feeding patterns, maintenance etc.>
Thanks again for all your help....
<No problem, Simon>

Worm ID 11/07/10
<Hello Mike>
Recently I have found an infestation of these worms in my tanks. I have seen some in my reef, and many more in my refugium. They appear to be bristle worms to me, which as I understand are not dangerous for my reef, but I would like to be sure that this isn't anything worse. Any idea what this critter is?
<A Polychaete of some sort; looks like a Terebellid to me. Bob Fenner>
Thanks, M

Bristle Worm/Friend Or Foe 8/2/10
Hey there crew.
Just a quick question if you don't mind. I'm assuming that what I have caught is a member of the Bristle Worm family. So my question is simply since I was lucky enough to see him at night and luckier still to catch him; Should he stay or should he go now! (singing). I know from what I have read on the sight that they are mostly harmless at this size but is it worth putting back in. Will it eat my pods, or eat snails when he grows and I can't find him again?
<Generally safe and good detritus eaters. More info found here.
Thanks as always
<You're welcome. James (Salty Dog)>
Jordan B.

Bristleworm/ Bobbit worm ? 6/3/10
Hello WWM Crew!
Thank you so much for making this fantastic website. I have relied on it for years!
Today I was surprised to look over and see this guy creeping out of a crack in a rock.
<Duh dunt, duh dunt...>
I have been all over WWM and seen a few examples of something like this.
#1 - http://www.wetwebmedia.com/polychaeidfaq3.htm
1st ID on the page looks similar, referred to as a Bristleworm
<Is definitely a Bristleworm>
#2 - http://www.wetwebmedia.com/polychaeidfaq5.htm
2nd photo on the page, which is a Eunice spp looks a lot like it
<And very likely a Eunicid, a member of this family... though I don't think Eunice aphroditois... "the" Bobbit worm>
I am trying to figure out if it is a threat that should be removed.
<Mmm, if it's bugging (worming?) you, or obviously attacking your livestock, yes>
I would love your opinion on it (and the best way to do it!)
<Bait it out remove it is so; enjoy it and show it off if not>
It has a very small diameter, 2-3mm (there is a pompom crab in the foreground to give you some idea)
but has easily stretched 3-4 inches from the crack/hole it seems to come from with no end in sight! It seems to
have eyes (It retreats very quickly when I move towards the tank)
<Oh yes; it does>
It's movement is similar to that of a tubeworm (the way it extends and retracts). I think the photos give you a pretty good idea but not perfect. It definitely has a face, a mouth, eyes etc.
Other information that might be useful is that I recently completely redid my aquarium. I added some new rocks and corals about a month ago so something could have come in on them. 3 weeks after the change in the tank, one by one, I lost the 3 small fish in there. They got a small amount of Ick which I attributed to the stress of the change immediately after changing the aquarium around, but it seemed as though their immune systems were dealing with it and that they were improving.
<A good explanation>
I attributed the loss of the first fish (tail spot blenny) to this stress as he wasn't quite right after the change; his carcass was partially eaten but it could have been a crab that did that. But the second fish (green bar goby) was not sick at the time of his death and had no head when I found him. The last fish was a small flasher wrasse and had what looked like a bite/tissue damage on him when I found him dead but had not showed signs of illness the previous day. All fish found dead in the morning when the lights came on and were swimming around ok the night before (before the lights went off).
When I found the fish like this I was concerned there might be some kind of predator in the tank as I had all of these fish for 1-2 years with no problems and they all went dead within 1.5 weeks (beginning 2.5 - 3 weeks after changing the tank around). I had dismissed my concerns about a predator until today because I thought maybe the fish had died due to stress related illness and maybe the Mithrax crab had eaten some of them (explaining the damage to the carcasses).
<A most likely scenario>
Does it seem possible for a worm this small to inflict that kind of damage on small fish?
<Is possible>
If it is not possible I am content to leave him in there as he is very interesting. Do you think it is a Bobbit worm?
<Another member of the family Eunicidae>
Do you think I should remove it? If so, what is the best method you recommend?
<Please read here re: http://wetwebmedia.com/polychaecompfaqs.htm
He seems so fast and I am not sure if the usual Bristleworm trap methods work on those guys, so they leave their holes?
<Oh yes... at night>
Thank you very much for your time and all you do for the aquarium hobby!
<And you for sharing. Bob Fenner>

Polychaete ID 5/15/10
Hi. I'm trying to identify a particular type of Bristleworm, so I'm hoping you can help me.
<Mmm, I "did a couple of years" ID'ing benthic Sedentariate Polychaetes for some studies at USD... there are thousands of species... need careful examination of the heads, podial elements...>
I've searched online and found differing opinions on what this may be. They are up to about 1-1/2 inches long, with long, narrow, segmented bodies. The "head" is very small, slightly narrower than the body, comes almost to a point, and is mostly a reddish-orange color. The "body" section is an off-white color. The "tail" end is a dark color, almost black. They live in my coral substrate and don't seem to really bother anything. I've seen my snails crawl right through a group of these worms with no apparent problems, and my Ophiolepsis sea star and micro stars have been living happily among them, too. I think they're neat because when they're startled
(like when the lights come on), they turn an iridescent, translucent blue color as they press themselves up against the glass and into tiny crevices. Any ideas? I was thinking possibly Eurythoe complanata, but I've seen varying reports of what that species is supposed to look like. Thanks for your help!
<Uhh... read here: http://wetwebmedia.com/polychaeidfaq2.htm and the linked files above. Bob Fenner>

Re: Polychaete ID - 5/22/10
Thanks for your efforts, but I'm probably not describing them very well. I would say that they can be best described as a long, narrow body consisting of a red section, a white section, and a black section. Looks kind of like 3 different color worms were lined up head-to-tail. With white podia all along. Most are only about 1/2" long, but some can grow up to almost 2".
Anyway, thanks for the help.
<REALLY need some good, well-resolved close-up pix... B>

Blue worm, "You put the moon in my eyes..." 3/9/10
Can you tell me what this is?
<Oh yeah... Please see here: http://wetwebmedia.com/polychaetes.htm
Looks like a common Hermodice sp.>
He is 12 inches long
and I can't find
one like him on line. His blue strip is very blue. Will he kill my fish or my bottom living things, i.e., crabs, star fish, snails etc?
<Might, yes>
I have looked everywhere on line and can't find another one that is red and blue. Thank you.
Marti Liska
<Welcome! Bob Fenner>
Blue and red bristle worm 3/9/10
<Yes Marti; same resp. as last>
I just bought a home with an established 14 year old 150 gallon salt water aquarium in it. I am learning fast. However, a few days ago I saw a ~10 inch long worm. I have established that it is a bristle worm from my reading however, I have yet to see a picture of one like this one. It is red on the outer edges and has a sky blue strip down the center of the worm.
Now, I purchased 4 little gobies and they died. Next, my clown fish was obviously getting sicker by the hour and died. Then another fish that had been in the aquarium for years died. The worm somehow got the dead fish in its "cavern" and pulled it under the rock and I believe ate it. I called my "fish man" who takes care of my system and he came right over and said that my nitrates were "off the chart." He did a 40 gallon water change and is going to do one every other day until we are all systems go again so I can get my new fish I have ordered from him. My two very large tangs are fine, so are my star fish and other things like snails and crabs (although I found one dead and out of his shell). I don't know what to think about that.
After the first water change all the fish started doing much better. But, this worm!!!! What on earth is this thing? Why have I never seen another one on line with a sky blue strip down the center? And most importantly, will he hurt my fish? He lives in the same cavern in the rock that my big blue tang and "his" cleaner shrimp live in and they don't seem to be bothered by him. He does spend a lot of his time under the rock but with a flash light I can see him in the back of the cavern at times and once he was out late at night. Why can't I find one on line with a blue strip and red edges? I do have pictures of him but they are not down loaded yet.
Please let me know if he will kill any of my fish or other living things. He is so
scary looking. I will email you a picture from my IPhone if that will help.
Thank you in advance,
Marti Liska
<Welcome! BobF>

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