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FAQs about Barnacles, the Cirripedia

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What is this creature???   11/4/11
We found this washed up on beach in Tramore. It is approx 6 Feet long and approx 2-3 feet in diameter excluding the hundreds of tentacles on it.
<Mmm, this is a mass of barnacles, Cirripedians... stuck on/to something. Bob Fenner>

Critter ID'¦ Barnacle, Maybe -- 11/04/10
Hi Crew,
I don't have a picture yet and am not sure if I can get one. I just bought a torch (Euphyllia) and there is something strange in middle of the tentacles. It is bullet shaped, white, very thin, about 3/16th of an inch wide and tall. When it opens a little spring like thing comes out and in. That is best as I can describe it. Maybe an alien space ship. Doesn't look like a living thing, looks more mechanical.
<<A barnacle perhaps 'have a read here: http://www.wetwebmedia.com/cirripediafaqs.htm >>
<<Welcome'¦ EricR>>
e: Critter ID'¦Barnacle, Maybe - 11/05/10
Right on, it really is neat to watch but I think I will get rid of it.
<<Not likely necessary'¦ Harmless if not beneficial -- and not destined to survive long-term in home aquaria. EricR>>

R2: Critter ID'¦Barnacle, Maybe - 11/24/10
Hi Eric,
<<Hey Sam>>
When I described my critter you guessed correctly and directed me to a page where others described this and in one case drew it.
<<Ah, excellent!>>
Well, here is a picture.
<<I see it 'neat critters, eh?>>
It is in a torch and the picture was taken after the lights had been off a while with only moonlight on. I could not get a picture of it closing. But it is just like when you close your fingers into your palm.
The hairs close in and curl as if trying to catch something and then it retreats back into its home.
<<Indeed 'this interesting little creature is 'sifting' small bits of detritus/plankters from the water column. Unfortunately most captive systems don't have such in enough abundance to keep these animals alive for the long-term. Do enjoy it while you can. Cheers'¦ EricR>>

Frogspawn Parasite, or just feeding, barnacle  04/02/09
Picked up a Branching Frogspawn from our LFS today, There are four heads, and directly in between two of the heads is a round piece of skeleton that sticks out about 1/4 inch farther then the other parts of the skeleton.
There is a hole on this piece, and periodically, little "feathers" come out, spin a little bit, then retract.
<This sounds like a barnacle. A picture would be helpful to confirm. Some can be trouble depending on their location on the coral.>
It kind of looks like a feather duster, but has only a few, (less than ten) very thin feathers, and they are arranged in a sort of crescent shape, not even a half circle. They really don't seem to be affected by light that
much. Is this a parasite, or is it a part of the coral and the way it eats or something. Thanks for your continued help.
<I don't know if I'd call it a "parasite" per se, but if it is a barnacle (and if it grows too big in the wrong place) it can cause some annoyance to the coral. I wouldn't try to remove it at this point though. Please do try to send a pic.
Sara M.>

Re: Frogspawn Parasite, or just feeding 04/02/09
I have confirmed through pictures online that it is a barnacle, so i should leave it?
<I would remove it IF it is easy to remove. Try breaking it off with a pair of needle-nose pliers. If it comes/breaks off easy, good... if not, I wouldn't go to any extreme measures to remove it.>
If a picture is necessary to tell me if i need to remove it, or to leave it, i can take a pic tomorrow morning when the lights come on. Do barnacles pose any threat to the other members of the tank?
<No. I'm not even entirely sure they cause frogspawn any trouble.
However, I have heard stories (and seen pictures) of barnacles growing in/on the actual polyps, close to the mouths. Some people swear that a barnacle growing in such a place has killed their polyps... but I don't know. I think the barnacles (filter feeders) just grow where they grow, and sometimes it's inconvenient for a coral.>
we have cleaner shrimp, clownfish, mandarin, hermits, all types of snails, open brain, lobos, torch, spaghetti leather, mushrooms, Acros, and pulsating xenias.
Sara M.>

Barnacles and Emerald Crab, comp.   3/1/09  Hello to all. Fantastic site, but so much info to take in. If someone's posted a question similar to mine before, please forgive me but I simply didn't see it. <Okay> I have a small 5 gallon "nano reef" (sort of) that I keep at my desk at work. I know many people advise against these, but I wouldn't have it if a co-worker didn't find some live barnacles that had washed up on the beach. She thought they'd live longer if one of our saltwater aquarists incorporated them into their system, but alas, common sense prevailed and no one wanted to risk damage to their healthy environments. So we put them in a 1 gallon backup tank. They've done remarkably well on a diet of plankton, phytoplankton, and baby brine shrimp, so I upgraded to a 3 gallon then a 5 gallon tank (which I should mention gets 20% water changes weekly). I started getting donations of live rock, a small anemone (also washed up on the beach), a mushroom coral, baby brittle stars, some small clams, and another cluster of barnacles. Sadly, I managed to kill some of the barnacles, the mushroom, and the brittle stars when I bought a new light for the tank that stayed on way too long. I was devastated. The light was dubbed "The Light of Death" and hasn't seen daylight since the incident. I don't use it because it doesn't seem like any of the remaining critters need it. Now my question- I feel very protective of my barnacles, as they were what opened the door to my ever-increasing fascination with marine life, so when a friend suggested I get an emerald crab and a blue leg hermit crab to combat my out-of-control algae problem I did. However, reading on your site, there's talk of the emerald crabs assaulting inverts based on opportunity and not need, so I'm questioning whether or not I've done something bad. Do you know if it will try to snack on my barnacles? <Mmm, a possibility... with time, if hungry> I just added the crabs today, so I hope I have some time to get a response. If you don't know (not likely) is there another source available for someone trying to raise barnacles? <None in the popular literature that I'm aware of... Cirripedians are very interesting shrimps indeed... Do keep good notes re your experiences... and consider writing them up. Much more "pure science" can be had by a library/bibliographic search. See here re: http://wetwebmedia.com/litsrchart.htm Bob Fenner> Thanks- Kerry

Re: Barnacles and Emerald Crab Thanks so much, Bob, for your fast response. I know most people find barnacles a nuisance, but they're really quite extraordinary creatures. I even sent out a video clip (pre-"Light of Death") to my friends and family of one of their more active sessions. I'd be happy to forward it on to you if you'd like. Mine are the acorn variety, straight off the beaches of Galveston, Texas. And, yes, I'll start keeping better notes; I suspected there wasn't much info out there on them but fail to see why. Keep up the excellent work- Kerry <Am trying Kerry. Thanks, BobF>

If I could bother you or one of the other crew members with a snail and parasite, ID,  9/27/08 Thanks, Bob!!! <Welcome> If I could bother you or one of the other crew members with a snail and parasite, ID, I'd appreciate it. I have gone through all the snail ID pictures and descriptions on all the 17 plus pages and of course, like most people, no one has a snail "just like mine". I had it narrowed down to the three most common ones people ask to have ID'd, Nerite, Collonista and baby Turbo, but I went through that site you have linked that shows all of the shells of those and I could find a few that were similar, but, of course, none "just like mine". They are primarily nocturnal but do appear during the day. I find them every where. On the glass. On the rocks. And on the corals, especially Zoas and leathers. I've even found some under the microscope in water samples that I couldn't see with the naked eye. It does have a pattern similar to a sundial but it has a smooth shell and doesn't have the pagoda shaped operculum. They also appear to have calcareous egg shells on the rocks but they are not round or sesame seed shaped, they are more like a pentagon. <I don't see these in my ref. works either. Am sending your query to friend and "shell nut" Marty Beals of Tideline for his input> The parasites I got off of a small piece of Acropora and Kenya Tree that I was given by a friend that I had in quarantine. <Mmm, don't consider these parasites... other than "space"... perhaps predators... Am pretty sure these are Ostracods> They were both fine for about 3 weeks and then the Acropora went in less than 3 days. It started losing tissue at the base and went right up to the tip. The Kenya Tree started throwing off it's own branches but is still doing okay in quarantine. Since the Acropora was already lost, I did a dip in Iodine and all that came off were these little critters. I dipped one of the branches of Kenya Tree and found the same thing. One picture is magnified at 40 times, the other is at 100 times. You can barely see the critter with the naked eye. It looks like a flea with shorter legs. Iodine dip doesn't seem to kill the critters. They were even alive after a day in RO/DI water. You know microscopes are addictive when you have a reef tank. <Ah yes> Once you think you've seen everything in your reef tank, you are sadly mistaken until you've seen it under a microscope. Thanks Everybody!!!!! <I don't think these small crustaceans were/are the root of the Cnidarians health issues. Bob Fenner>

Hi Bob, Is it me, or do those look a lot like larval cirripedes? Cheers, Neale <Mmm, you may be right... will amend. Thank you, BobF>

Barnacles 09/04/2008 I have a question regarding barnacles that I have been unable to find an answer to. <<Lets see if we can help then>> I am currently cycling my first marine aquarium (I've got some experience with freshwater) with Fiji live rock and just noticed that the two dozen or so acorn-type barnacles that came on it are actually alive. It is my understanding that the barnacles will eventually expire from lack of appropriate food. According to Conscientious Marine Aquarist, these barnacles could be hosting parasites that will attack the gills of any fish I introduce. The first livestock I plan to add is the common cleaner shrimp Lysmata amboinensis. Will the shrimp be sufficient to wipe out the parasites, or should I wait until the barnacles have been eradicated to add the shrimp? Is there a way to get rid of the barnacles? Will the die-off of the barnacles cause another ammonia spike? Any enlightenment on the subject would be much appreciated! <<To be honest, most barnacles do not last much more than a couple of months in captivity. Its not something that I would be concerned about. Thanks for the questions, please do read more here including linked articles and FAQ's http://www.wetwebmedia.com/cirripediafaqs.htm ...Thanks, A Nixon>>

Bizarre Creature Identification  6/9/08 Good Morning Crew, <Good evening Toni, Mich with you tonight.> My fiancĂ©©' and I are new to saltwater aquariums and we are very excited about our new found hobby. <Welcome to the briny world.> He loves to sit and watch for what seems to be hours on end! He reads a lot about things on the Internet and we stumbled across your site. It's truly a God send! <Glad you have found it helpful.> We have a question. We acquired this very strange live shell, from the coast near Corpus Christi. <OK.> It looks like a million individual mouths that continuously open and close. They each have a feather like tongue that they stick out each time they open their mouth. The tongues resemble feather dusters, but the look like little feather claws that the creature waves around before it draws it back in. It is so strange that its kinda creepy. I have attached a picture. Can you identify it? <Hard to tell from the picture, but your description sounds like a barnacle.> I've Googled everything I can think of, but no luck. We have a 25 gallon tank. It's still fairly new, maybe a month 1/2 old the water levels are holding at the levels the pet shop says they should <Best not to rely solely on the pet shop. Please educate yourselves. Perhaps do some reading on our site.> and it doesn't seem to be negatively affecting anything. We have a Peppermint shrimp, damsel, a goby, and several pounds of live rock. <You have a very small system, please read and be careful of how much more livestock you introduce.> There also seems to be another creature that rode along with it. It isn't very clear in the pic, <Mmm, I'm not seeing it in the pic, sorry.> but it is small and bluish. It seems to have some sort of tentacles and it came from the shell and has now attached itself to the live rock. We thought it was a sponge or coral or something, but now I am convinced its an animal. <Actually sponges and corals are animals.> Any ideas on what this might be? <Mmm, possibly an Aiptasia or anemone of some sort, but is really a guess at best.> I am concerned because these were not store bought. Are they dangerous? <The barnacle is not, though they typically don't live long in captivity.> Please help! I'm going crazy trying to figure this out! Sorry for the poor quality pictures. <Yeah, not the best, next time try using the macro feature on your camera.> How are others getting such great pictures of the life inside their tanks? <Use the macro setting, usually looks has a symbol that looks like a flower, typically a daisy.> You can barely see the bluish-purple creature its on the left at the bottom of the rock, but it looks like some sort of soft bodied snail like thing with short blue spiky looking tentacles one end of its body. <That sounds like a Nudibranch, but if it is relatively stationary it is likely not.> The rest of it looks textured with little bumps, but not tentacles. <Definitely look for the macro setting and if you can get a better image please feel free to send it in. I will gladly try to help you figure out your mystery creatures! Cheers,
Toni McCrary


Cirripedian ID    7/17/07 So I was helping my cousin-in-law find plants for her new aquarium down on the docks and we found a bizarre animal that I can't identify. I found them attached to a piece of seaweed with a silvery white, bubbly substance. The animals themselves are difficult to describe. The resemble something I have seen before, that look like clams living on the sea bed, but the clamshell sits suspended above the seafloor by the foot of the clam. In this case the foot is a tube (attached to the other seaweed). The shell isn't actually a shell at all but looks like a bivalve. Out of the 'shell' pop 1-2 dozen little arms, and they seem to be doing the feeding. There is also a black dot behind them that could be an eye. They are a pale gray-white, and only about an in in length overall. We are on the coast of Maine so I'm going to have to say these guys prefer cold water to warm. One more thing is the seem, oddly enough, to be aggressive. When I stick my finger in the bowl they try to wrap around me. Anyway, I know this is a pretty weak description, but I can't seem to find a picture online to send you. I've lived my whole life on the New England coast and I've never seen on of these guys <Well, it's impossible to say without a picture, but you seem to be describing stalked barnacles. Many stalked barnacles attach to floating objects and live in colder water.> Thanks! -Aaron <My pleasure. Sara M.>

Strange "hand" Coral Barnacle (Pyrgomatid)   4/24/07 <Hi Harry, Mich here.> I purchased a nice size torch coral 3 days ago, and have noticed this strange looking white thing that appears out of its hole (about 1/8 of an inch in dia.) It appears every few seconds and seems to be coming out then popping back inside its hole. The "thing" in question has approx. 10 to 12 very thin white fingers . Attached are 2 pics. the first one is the hole and the second is the "thing" coming out of the hole,,,, hope the pics help <Yes, photos are usually very helpful.  This is a barnacle.  It shouldn't do any harm and will likely not survive more than a few months in captivity.> Thx for your help,,,,,,,,, Harry B
<Welcome!  Mich>

Coral gall barnacle  3/16/2007 Good Evening Crew! Good day to you Brad!  Mich here. I hope all is well at the WetWebMedia center.   <Making progress!> I am writing with a "Friend or Foe" question.   <Always try to be friends here!> Attached please find a crude sketch for discussion.  It is intended to depict a small (approximately 2mm long) sweeping appendage of an unknown filter feeder.  This "catcher's mitt" looks much like the straining appendages seen on porcelain crabs, and on many barnacles.   <Most all filter feeder are friends not foes.> <<Unless you're very small.... Heeeeeeee! RMF>> I have a newly acquired Frag of a Montipora digitata that is host to a half dozen or so of these solitary sweeping creatures and one other fellow that is slightly different.  From my reading these appear to me (the layman) to be small Coral Gall Barnacles.   <Your sketch resembles barnacles.> Except that the one tiny little fellow appears to have two legs sticking out the front door of his cave.  Could he possibly be a Coral Hermit Crab?   <Not likely a Coral Hermit Crab (Dardanus tinctor).  Maybe an Acropora crab or a coral crab.  A photo would be most helpful here.> Currently, this coral specimen resides in my 37 gallon hospital tank.  The question is: will it harm my 130-gallon reef tank to introduce these creatures along with the Montipora?   <Unlikely.> And, if so, what is your recommended plan of action? <Watch and enjoy!> As always, thank you for your thoughts and for your wonderful site. <Thank you for your kind words.  Mich>
Brad in Basalt

What the barnacle? Nano-Marine Issues   3/1/07 I searched your sight and didn't like what I read (darn you guys). <..Not usually what we hear but...okay.> Anyway, I believe I have a barnacle problem. <Okay.> Recently, I was unable to do my mandatory 50% water change on my 2.5 nano. <I see.> I was having great success until recently due to one problem a couple months ago with a heater that wiped out half my tank (I lost a fish, a worm and some snails) <You had a fish in 2.5 marine nano.....now I am not liking what I am reading.> and another one about 3 months later when my emerald crab died who kept the tank utterly spotless (in fact this crab was the savior of the tank).   <You are keeping too much in this tank.> In both instances, I rallied the tank for several days with several water changes until things tested better. But due to guilt and uncertainty as to why the emerald died, I couldn't bring myself to buy another one for about a three weeks now.   I usually have nitrates no matter what, <I bet...> but can keep them at bay with consistent 50 % water changes (no protein skimmers in market yet to speak of). This is the first time in a very long time I didn't due my water change every week (I changes it this past weekend.) Since the death of the crab, green hair algae went nuts as wells as a lot of grayish like bullcrap <?> sticking to the rock, the later of which I can shake off rock by squirting a feeding tube at it. Now, in the past week, after I did my (only one week behind) 50 % water change, plus two 20 % water changes in past three days, I have BARNACLES every where. <Feed off oh high nutrient levels.> The nitrates are around .25 to .50 ppm. <You don't any chance mean 22rppm or 50ppm do you?. The amounts above are nothing really as far as nitrates are concerned.> I did go a head and buy a smaller baby emerald on Monday who is holding his own just fine for now (he is eating, cleaning his/her self).  I also have a small male/female set of dragonets <Uh-oh, methinks these animals will be short-lived, please read WWM re: dragonet behavior.> (wrongly called scooter blennies) <Well yes, but this is a commonly used...well common name for them, the only way to be sure is to provide scientific names.> and one small clown fish, about 8 snails in total (4 very small and 4 medium sized of varying species) and 6 hermits (4 very small red Mexicans approved by this site b/c I recall checking and 4 small to medium sized blue legged hermits) and one sea cucumber (tiger) who cleans all my sand until its is pure white. <Your nutrient issues will only continue, this tank is over and inappropriately stocked my friend.> I also have or had a worm (feather duster) who may be dead b/c he hasn't come out since day before water change (guy at store said they grow their heads back and to keep it and wait and see, is this good advise? Should I lose it?)   <They will recuperate in ideal conditions which these are not.> My question is, will these go away? <Not in his tank with it's current conditions.> How many additional water changes should I continue to due besides my 50% every 7 days? <Mmm...as much as possible until you can find homes for these animals.> Do I have to toss all the rock/sand and start over completely due to inevitable larvae break outs. <Read WWM re:.>   I have visible copes/amps and micro stars still living in the tanks as we speak.   It is still established and I would like to not have to toss everything and start again. <I would suggest some animals for natural predation but not in this size tank, the barnacles are just a symptom a major root problem.> I am pulling my hair out over this.  I have a 10 gallon nano that is perfect because of your site's great advice (it has countless goodies and night diving w/ the flash light is awesome and endless!). I can do this small nano too, I think? <Not with what you have in it.> Please save my tank and my sanity. <Read here my friend: http://www.wetwebmedia.com/nanoreefsysart.htm .> Sincerely Colleen in Long Island <AdamJ in So. cal.>

Barnacle in Tubastrea, Concerns Unlikely to come to Fruition - 02/09/2007 Hello to the wonderful crew at Wet Web Media, It's Brandon again.   <Hi Brandon!  It's Mich again.> I am writing because I had a thought, while watching my Sun Coral.   <Hmm, maybe I could send a couple a people to see your Sun Coral so they might have some thoughts.> I bought two colonies, because I knew that the LFS they were in was either going to starve them, or sell them to someone who could not care for them.   <"Rescue" is not necessarily the best policy here.> I will admit that I was not terribly interested in hand feeding two colonies of Sun Coral, but I have grown quite fond of the guys, watching them eat and all.   <I hope you do not tire, another reason why rescue is not always a good thing.> I noticed that there was a creature inside one of the colonies.  I have identified it to be some species of barnacle. <OK.> My concern is that all things grow, and I am quite sure that the barnacle will grow, resulting in one of two outcomes.   <Actually barnacles usually don't do well in captivity and typically starve.> Outcome one, the barnacle splits the colony, and assists me in propagating it.   <Unlikely.> I am hoping that this is the way things go.  Outcome two, the barnacle grows larger, but is not able to break the colony, and dies a horrible pressure death, causing me to have to take the colony out, or risk the reef.   <Also unlikely.> I have already looked at pulling the barnacle out and relocating it, but he is bigger than the hole he lives in.  I was hoping that someone at WWM had run into something like this before.  I have been reading an article that Anthony wrote regarding coral propagation.  I am planning on buying his book as soon as I know the name of it ;).  Hoping that you guys could tell me that too. <"Book of Coral Propagation, Volume 1: Reef Gardening for Aquarists"  by Anthony Calfo.> If I have to split the colony on my own I was wondering what would be the best way to go about it without loosing either creatures. <Unfortunately, I don't think this will be an issue.> I also recently asked about a Trachyphyllia.  I was concerned that it would die because of a loss of tissue, and algae growth on the skeleton.  I moved it out of the light to a slightly shaded area, and it is doing much better.  So thank you for the help Mr. Fenner, as you were the one that answered me on this.   <He will see.> I would also like to thank you all for the help that you have given me in the past, <You're welcome.  Glad you have found it useful.  -Mich>   Brandon R. Foster

Barnacle in Tubastrea, Concerns Unlikely to come to Fruition - II - 02/11/2007 Greetings all, <Greetings to you Brandon!> I had a few concerns that the barnacle would starve to death as well.  But I have been observing him, and he seems to be eating quite well.   <One can only hope.> I have actually observed him sticking out some sort of feathery hand like appendage, and "catching" food items with it.   <Yes, typical behavior.> I have been feeding a mix of Mysis, and phytoplankton.  It is pretty interesting.  When the Tubastrea eats, the barnacle eats.  I have frequently seen him eating, actually I can't recall not seeing him catching things.  The only time that he isn't seen is when one of the larger fishes swims by.  As to the rescue.  I am kind but not fool hardy.  I waited for about three weeks before purchase on the sun coral, and I read all that I could on the site, then I read http://www.reefs.org/library/aquarium_net/0797/0797_3.html.  The article by Eric Borneman.  Armed with this information, I felt that it was easily in my capability to care for these organisms.   <Thank you for making an effort and educating yourself, I was merely commenting on your self described questionable commitment to hand feeding.> I have been feeding them nightly. <Very good.> I have let them continue to be nocturnal, because I leave work when the lights are already off.   I have noticed  as of late that they will come out any time that I add food to the tank, and I have even seen them catching free floating food items.   <All good signs.> This encouraged me, and I think that it has even lightened my load a bit.  By the way, I did QT them for a month, during which I did feed them.   <Very good.> I didn't notice the barnacle until a few weeks ago. I saw him come out.  I thought that it was something with a tongue.  I watched a bit closer and realized that it was the aforementioned feathery hand like appendage.  I have had both colonies, and the barnacle for a few months now.  I thought that if he were going to starve he would have done that by now. <Maybe, maybe not.> Thanks again, <Welcome!  -Mich> Brandon R. Foster

Identification question--Barnacle Bill These little creatures (one of them, not the grouping) are about the size of my little fingernail... photos taken at Edisto Beach in South Carolina about 3 weeks ago. Can you tell me what they are? <yes my friend... barnacles. Do I win a hairy Kewpie doll now :)?> Thanks, Muddy
<cloudy but still standing, Anthony>
identification question These little creatures (one of them, not the grouping) are about the size of my little fingernail... photos taken at Edisto Beach in South Carolina about 3 weeks ago. Can you tell me what they are? <Barnacles... likely Lepas anatifera, the Smooth Goose-Neck Barnacle. Bob Fenner> Thanks,

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