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FAQs about  Brittlestar Behavior

Related Articles: Brittlestars, Sea Stars

Related FAQs: Brittlestars 1, Brittlestars 2, Brittlestars 3, Green Brittlestars, Brittlestar ID, Brittlestar Compatibility, Brittlestar Selection, Brittlestar Systems, Brittlestar Feeding, Brittlestar Reproduction, Brittlestar Disease, Seastar Selection, Seastar Compatibility, Seastar Systems, Seastar Feeding, Seastar Reproduction, Seastar Disease

"Making a living the pet-fish way, slithering sideways..."

Starfish behavior     12/29/18
Hi Crew!
My serpent banded starfish has been doing some odd behavior, staying near the top as of late and also sometimes acting like a tripod so to speak.
<I see this>
No significant changes other than upgraded lighting. Ammonia, nitrates, nitrites undetectable, dKH 8, cal 420, Mag 1350. Tank has been established for almost a year since I have rebooted it. Any ideas?
<Yes; this is "reproductive behavior"... though your Ophiuroid won't be reproducing... echinoderms are dioecious; takes two "to tango"... It's sort of out looking for a mate>
<Cheers, Bob Fenner>

Another Ophiuroid hlth., beh. question      9/6/12
We just bought a serpent starfish last night. We are new to Saltwater tanks. We did not do the drip acclimation process as I knew nothing about it so that may be the problem. When I released it into the tank, it wandered across the tank. When we checked on it this morning it was in the same position it was in last night so we gave it a nudge with the fish net and it is stiff as a rock. Is this normal? Or is it dead?
<Mmm, I wouldn't give up just yet... watch it for another day...>
I have tried to research it and some websites say they get stiff as a defense mechanism but to stay in the same exact position for so many hours? Help!
<Please read here: http://www.wetwebmedia.com/britstardisfaq2.htm
and the linked files above. Bob Fenner>

Re: Invertebrate Disappearances  11/8/09
Thank you so much for all your help, I feel kinda silly now for over reacting but while setting up the trap last night some of the food slipped out and guess what? Yep, the brittle stars arm shot out to get it :)
<Very common>
he is a Ophiocoma as far as I can distinguish, once he settles in if I can get a pic I'll send it. I am putting the loss of the other inverts up to an issue my mother was unable to detect in water quality but it seems to have
settled after the many water changes since then, which is what I was doing until I prematurely freaked out over this star fish :). I'll see how it goes for a couple weeks and look into replacing the rest of the inverts. Do
you know of anything that has a taste for red hair algae?
<... please see WWM re identification... likely Cyano/BGA...>
Everything I found only likes the green and just picks at the red as a last resort... I have fixed the cause of the out break, (old lights and high phosphate) but I'm not looking forward to scrubbing rocks.... The
light issue along with my urchin really did a number on my coralline so I'm trying to get that back to the level it was when I left.
<With time... Cheers, BobF>
Re: Invertebrate Disappearances
This is the closes pic I could find to what looks like my brittle star and a pic of the serpent star
<... I take it these were lifted, copied w/o permission of their owners.
invert. pics
Yes they are not my pics, Forgive me I only meant to use them to better give you an idea of the star fish I was dealing with.
<Ahh! Understood>
I should have given credit where it was due and will do so now, the first pic was found at http :// www . reeftopia.com/images/redbrittlestar1.JPG,   and the second at http :// www . livestockusa .org/ tigerbrittle . jpg .
<Much better. Because they are neither my nor your property, best to give these addresses for others reference>
As they are not my pics I have no right to allow them to be reproduced in any manner I merely wished to give you a visual of what I was talking about. Thinking about it now it would have been best to give you the websites rather than copy the pics. I never intended to take credit for them. I will try my best to be more conscientious in the future.
<No worries Jen. B>

Brittle Star Making A Home---8-18-08 Hi- <Hello there.> I recently purchased a bit more live rock for my 24g cube & got a small black brittle star 'hitchhiker" which has remained hidden thereafter. It was not acclimated into the tank as it fell out of the rock & crawled away. It has been about 5 days & not been seen day or night- ammonia, nitrite & nitrate levels all within parameters. <Sounds good.> My question is how concerned do I need to be about it dying & polluting the tank, <Not at all.> how will I know if I never see it? Should I look for it, which will cause me to tear apart the live rock & caves, etc. I tried the other day & could not spot it. <I am sure he is fine in there. I wouldn't go to tearing rock apart to try and find him.> The tank is only 6 weeks old, lots of nice algae growth & inhabited by lawnmower blenny, 2 green Chromis, a rock beauty all doing well & eating & also has small sand sifting star....LFS has advised not to worry they are very elusive & nocturnal......Oh and any need to feed extra to be sure he [brittle] has food available? <Your LFS is correct. You most likely will not see much of this guy at all. I have one in my tank and I may see him once every six months or so when I am re-laying the tank. They are pretty self-sufficient when it comes to feeding so you do not need to add any extra food. These are great tank inhabitants and will provide good "maid service" so to speak in your tank. Nothing to be worried about at all. ---Yunachin> Any help/info. would be appreciated! Bob

Auto-Legless brittle stars    7/16/07 Hello, I recently bought 15 blunt-spined brittle stars from an aquarium. <Are we talking about Ophiocoma echinata? Where did you get them?> I've had them for five days. They have been doing well the first day except for three of the brittle stars. After the weekend, I came over to check on them and half of the brittle stars were severely damaged. <Do you mean half of all of them or half of the ones that weren't doing well?> They autotomized all their arms and only their central discs remain. <Yikes! Are you sure they autotomized? Is it at all possible that they just died and then got torn apart after they were dead? Are any of the legs still moving?> In the tanks, I can see trails of bits and pieces of their arms everywhere on the sand. <These stars can autotomizes at any segment but I've never heard of them autotomizing at so many segments all at once though. That is quite dreadful.> It is quite sad. I don't understand why these brittle stars are behaving so strangely. I feed them daily and check the salinity of the water twice a week. I also do some chemical water tests. <How big is the tank? What are you using as a filter? What are your salinity, temp, etc? Is there anything else in the tank? Which tests did you do? Sorry for all the questions, but it's difficult to say what might be happening without knowing a lot more about the system.> The self-mutilated brittle stars have a clear membrane-like substance surrounding their central discs. Are they dead or will they still regenerate? <Theoretically, the disks can regenerate legs if the stars are still alive. However, I don't know if they could survive with no legs at all. Regeneration requires a lot of energy (more energy than just normal growth). And I don't even know how they'd be able to move without any legs.> Why are these brittle stars behaving this way? <I have a few suspicions, but I would have to know more about your tank. If you added all these stars at once to a relatively small, new tank, you could have ammonia in the water. If it's just 3 of the stars dying this way, and it's a small tank, it might be that the other stars are attacking those 3 for some reason. And again, is it possible they just died and fell apart?> By the way, I am using these brittle stars in an experiment but haven't done quite anything to stress them because I was afraid they would die. <Yes, something is really wrong. The only thing I can think of that would cause a brittle star completely autotomize like that would have to be a serious toxin or a massive attack by other animals. What kind of water are you using? Is there any way copper could have gotten into the tank?> Thank you very much, <No problem. But I do hope you write back with more information so we might be able to help you more. Best, Sara M.> Lea

Re: Auto-Legless brittle stars    7/17/07 Hello again, Thank you so much for replying quickly. I assumed the brittle stars that I bought were Ophiocoma echinata because they look similar to the pictures online. The store that I bought it from didn't know what the species name was, but they said they got it from the Atlantic. I attached some pictures of these brittle stars for you. I hope you can identify them better than me. <For some reason the pictures didn't come through with this email. Huh.> I'm sorry that I didn't explain in detail what had happened earlier. Seven out of 18 brittle stars basically self-mutilated themselves. Three of them started autotomizing the first day that I got them. The other four probably were damaged over the weekend. When the brittle stars autotomized their arms, they autotomized it by segments. However, some of them cast off almost their entire arm, which surprised me very much. The longer autotomized arms moved for a short amount of time, but the small segmented autotomized arm did not move. I also attached a picture of this incident. <Ok, I'm just wondering if this is true autotomization or if the legs might be necrotizing. Usually, autotomized legs move (wiggle around) for a long time after they're detached.> The tank that I have is 15 feet tall. <Seriously?! Did you mean 15 inches or 1.5 feet maybe?> I have 14 tanks that are all connected together (a closed circuit water system. There are seven on top and seven on the bottom. I keep my brittle stars on the bottom. In the tanks, I have a thin layer of sand. I did a water test today. I am using salt water. I use deionized water and mix ocean salt with it. I don't think any copper went in the tanks. Here are my results: salinity - 1.021 pH - 8.2-8.4 nitrate - 0 nitrite - 0 calcium - 17 drops ammonia - 0.5 (probably because of the dead brittle star bodies) <Hmm...I suspect this might be the problem.> temp- room temperature When I first got the 15 brittle stars, I put them in one tank. The next morning, I saw pieces of the arms in the sand so I separated the brittle stars to prevent them from hurting each other. I don't know if I made it worse. Do brittle stars survive better if they are together in a group? If so, why do they? <Separating them was a good idea.> Thank you so much for answering my questions. You have helped me a lot. I apologize for not introducing myself properly. I am a senior in high school and am currently doing research on these brittle stars. I am very interested in the relationship between regeneration and autotomy in these brittle stars. Their behavior is sometimes unpredictable though. <Nice to meet you. :) Do you know how to use Google scholar? If you're up for a challenge, there are quite a few hard core research papers on autotomy and regeneration in starfish.> I am trying to quantify their behavior but I don't know the best way to go about it. Brittle stars are known for their fast movement compared to other echinoderms. However, I don't know how to equally quantify their locomotion. They aren't like mice in a maze. They go in unpredictable pathways (i.e.. up the side of the tank, in a corner, etc) <Well, this might be tricky. I know of one way you could do it theoretically, but it would be way too much work and expense for one person. But um, there might be another way too. They might not go through a maze, but they can sniff out food. You might be able to race them in a big enough tank if you starved them for a few days and watched to see which star got to the food first. But that would only be a relative measurement, and a rather crude one at that. Honestly, I don't know of any practical way it could be done properly. It is an interesting question though.> I also have trouble quantify how much they eat. I feed them flakes and fish pellets, but so far they haven't been eating them very much. What type of food do they most enjoy? I'm sorry for asking you many questions. I try to look up things online, but haven't found very useful information. <You're not alone. This is one reason it's difficult to do experiments with animals in aquariums. All you can really do is make sure you feed each star fish the same amount. Granted, some will eat more than others, but there's not much you can do about that. You have to think about what you can and can't measure. You can measure their weight, their size, and maybe their color to some extent...> I thought it would be a better idea to ask a researcher instead. What type of research have you done with brittle stars? They truly are interesting creatures :) <Yes, you should definitely ask a researcher if you know one to ask. At the very least, a researcher should be able to help you design the experiment. I haven't done any research with brittle stars. I have done research with piglets and rats. It's a little easier with terrestrial animals, but not much. Good Luck :-), Sara> Best regards, Lea

Serpent Starfish, Normal Behavior  2/7/07 Hello, <Hi Kelly!  Mich with you today.> I have a Serpent Starfish in a tank that has been established for sometime now. <OK.> He has been in the tank for about 4 weeks and never comes out. I don't sleep much sometimes and am up for 24-48 hours at a time here and there. <Yes, unfortunately I can completely relate.> When I can't sleep, I sit and watch all of my critters in the tank. <Me too!> I watch when the tank lights are off and when they are on and I never see my Serpent Star come out ever. He hides under one specific rock and never comes out. I can see his tentacles once in a while searching for food, but that is it. Will he ever come out of hiding or is this normal for them to do? <Is normal.> I am beginning to wonder if he is okay. <Is fine and likely happy.> I have moved my rocks around and he will race to get back under whatever rock is closest to him and stays in hiding. <Absolutely normal.> I haven't seen any abnormalities in his structure and he hasn't lost any of his tentacles yet. <Don't say yet!  I think you star is happy and health.  No worries here my friend!> Thank you for any advice you can give. <You're welcome!  -Mich> Kelly

Is my brittle star dead?  Concerning behavior.   2/3/07 Guys, your site is excellent congratulations. <Hola Reynaldo!  Muchos gracias!> I'm rather new to salt water aquariums but have a lot of experience on freshwater ones. <Muy bien!> However it has not been easy. <Si.  Often challenging.> I like others, have started with a small 20 gallon tank, and have two damselfish: a blue and a three stripe. However in my local aquarium, down in Mexico, I bought a brittle star (dark brown) which I thought of to be cool. I was told it would eat detritus and that's it. <Will eat detritus and other meaty foods if offered.> Just a couple of days after, I noticed it to be 'stiff'. Then turned it on its belly. <I think you means it's back, correct?> It did not try to turn around but slowly started to flatten down. the mini-tentacles under the tentacles themselves are moving, but I had to turn the star around again to its upright position. No arms have fallen and no decomposition seems to be taking place. <This is very good.> Does this stiffness indicate imminent death? <No, but I would watch carefully.  His behavior is concerning.  Usually brittle stars and other Ophiuroids will upright themselves relatively quickly.> Thank you in advance!! <De nada mi amigo!> Reynaldo Suazo Toluca, Mexico <Salude!  -Mich>

Question about Harlequin Serpent Stars longevity   1/24/07 To whom it may concern,     We have had a harlequin serpent star in our tank for  almost thirteen and a half years, but recently have noticed it is not sending  out its arms when the tank is fed for the first time( it would always search for  the food before). <Mmm... any other organisms acting odd? Might be just senescence... am getting there myself> We can see a couple of arms, and they sluggishly move, but  cannot see the star's body so it is still alive, but cannot tell it's condition.  Obviously, 13.5 years is a good run, but as we contemplate it's possible demise,  we wonder how long can these stars actually live? <Mmm, don't know... other echinoderms have demonstrated great longevity> The only other inhabitant is a  9 year old maroon clown, and it is doing fine eating well, and swimming to the   feeding station when I give it the signal - so it appears the tank is still in good order. Just curious about the life expectancy of the star, and of course  hoping it is just a temporary dormant phase!                                Thank you,                                             Ourecho <Other than checking water quality, doing pre-emptive water changing, use of chemical filtrants... and reading on WWM re Ophiuroid health... Not much to do here. Bob Fenner>

Brittlestar Behavior - 10/15/06 Can you shed some light on my brittle starfish? <<I'll try>> I have had him a few weeks, been great fun to watch him he has been dancing at food time.  Last couple of days he's been lifeless. <<...?>> He is still alive, moves his legs a bit but has not moved his body. <<This is not uncommon behavior.  Many times these Ophiuroids will find a safe/secure spot and merely "wave" their arms about to gather food, not moving their bodies at all>> He right in the front of the tank the tank is 190 litres. Got clownfish, hermit crabs, tangs, another brittle, little red star, fish algal crap just shed his skin today, <<?>> few bits of living rock with flowers on out and open.  A few other fish don't ask me they names but everything looks healthily not my tank its my partner's. <<I hope your partner has a better idea of what is in the tank as well as how to care for it>> I just feed them. <<I see>> Is he ok? <<Probably>> The other fish seem to be going to look at him.  They are not bulling him or anything but they never hovered with him before.  Any suggestions? <<Do some reading here ( http://www.wetwebmedia.com/brittlestars.htm) and among the links in blue.  Regards, EricR>>

Brittle Stars Not Hiding...(Starving Maybe?) - 08/29/06 Hi Bob and Team: <<Team member EricR here this AM...>> I recently added two Brittle Stars to my reef tank.  They're my first foray into stars and I purchased them as a clean-up crew compliment to my Mexican Turbo's. <<Excellent scavengers/detritivores>> My question related to Brittle Star's is three-fold.  (1) I've noticed that the body of both BS's is concave - completely dented in.  Is this the way they're supposed to look? <<Mmm, nope...not in my experience.  Are they eating/become more active when food is introduced?...do they have "enough" to eat?>> 2) They don't seem to do very much, at least as far as I can see.  They're mostly out of the reef during the day and sit almost motionless on top of a rock.  Is this normal behavior? <<No again, usually quite secretive/photophobic.  It is not unusual to see an arm or two waving about, but Brittle Stars generally avoid full exposure to the tank lights>> Should I supplement their algae and detritus eating with some brine shrimp or other food source? <<Supplemental feeding of "meaty" foods may indeed help/be what's needed here.  They absolutely will "love" shrimp pellets>> Best to you all. Scott Sunshine Ft. Lauderdale, FL <<Good luck with the approaching storm (Ernesto).  Regards, Eric Russell...Columbia, SC>>

Bristle Star??? Brittle? Health... env.   7/11/06 Good Afternoon, I recently purchased a bristle star from my LFS, although I am not sure what kind of bristle star it is, <Obviously... an Ophiuroid? Is called a Brittlestar... though Bristle star is also quite descriptive> it is black with feather like bristles along each arm.  But anyway, I dripped acclimated him for 2 hours, and when I put him into the tank, he rolled over on his back (mouth towards the sky) and just laid there. <Ooops... trouble>   So I left the lights off through the morning hoping to help him adjust, and praying he would have moved by now, and he did about 6" on his back still.  My water quality is great pH 8.2, 0 amm., 0 nitrites, and 5ppm nitrates, temp. 78.2 degrees.  So anyways, I tried to feed him small pieces of frozen food, but he just laid there beside it.  And I have asked everyone and no one knows what I am talking about.  Somebody throw me a bone? Thanks, Michael <Mmm, something is "too different" or amiss with your water quality... Likely alkalinity and/or biomineral content... Please see here: http://www.wetwebmedia.com/brittlestardisfaqs.htm and the linked files above. Bob Fenner>

Harlequin Serpent Star Concerns - 06/07/06 I was hoping I might impose on you for a little information. <<Impose away! <grin> >> A few weeks ago I got a beautiful harlequin serpent star - to whom I have become quite attached after he wrapped one of his arms around my finger when I was working in my tank. <<Have kept these before myself...neat and attractive critters>> Granted, he was probably trying to eat me, but still... <<Hee!>> Anyway, also in my tank I have a blue-banded coral shrimp.  I have heard that the regular banded coral shrimp have been known to eat fish, but mine is one of the blue ones, quite small and secretive -and seriously lacking information about on the internet. <<Indeed...would expect behavior to be quite similar to their larger brethren...just on a smaller scale>> Last night while peeking in between the rocks, I saw my geometric pygmy hawk perched smack-dab in the middle between the shrimp and the serpent star and neither one of them bothered him. <<Not uncommon really.  These stars are mostly detritus feeders and usually won't attack a "healthy" fish unless starving.  Keep the star and the shrimp well fed and you likely won't have any issues>> However, my purple Firefish has been MIA for several days, and I assume he has been eaten. <<Agreed...but probably post-mortem.  Firefish are always "touch and go" in my opinion.  I find them very sensitive/susceptible to stress from just about everything...and likely to go "missing" at any time>> I had the Firefish and the shrimp for quite a while together before adding the serpent star.  I also did what I thought was good research on the serpent start before putting it in my tank.  Would he have eaten my Firefish? <<Is always possible, but I doubt it...unless it found it dead/dying already...is what they "do">> I see him pulling in Mysis shrimp and eating them, should I supplement him with bigger pieces of shrimp? <<Probably not necessary if you are feeding a couple times a day, but it wouldn't hurt to supplement the star's diet (the fish and shrimp too!) with a quality pelleted food (New Life Spectrum gets my vote), if you wish>> Thanks for any help you can give me on him.  He's beautiful and I don't want to have to remove him, but I would also like to keep a purple Firefish in my tank as well. <<You can try the Firefish again if you wish, I don't think this serpent star is a large risk>> Thanks, as usual, for your infinite wisdom. <<Mmm, if only that were true! <grin>.  Regards, EricR>>

Harlequin Serpent Star Concerns II - 06/07/06 Eric, <<Rebecca>> Thanks for your help, but I have great news to report!  Last night I reached into the chamber of my nano that I have converted into a mini refugium (underwater fountain light and a handful of Chaeto) to shake some pods into the tank, and I heard some wild flipping noises. <<Ahh...>> Guess who was in my refugium?! <<Um, little purple dude?>> So I guess he was in there since Sunday when I did a water change. <<Indeed>> He seems OK, other than some tissue loss on the front half of his anal fin (I'm hoping that will grow back quickly). <<Will likely be fine>> I'm sure he had plenty to eat in there! <<Agreed>> I hope I have some pods left.  This is the least neurotic Firefish I've ever had. <<Lucky>> I scooped him back into the tank and he went into his cave for a few minutes, then he was back out in full view, ready to eat! <<Must feel quite comfortable in your setup>> I'm so glad he didn't get eaten! <<Me too!>> Thanks again for your help! Rebecca L. Dishman <<Always welcome.  Regards, Eric Russell>>

Black Brittle Star Not Stirring My Sand Bed - 12/02/05 Hi all, hope this message finds you happy in your free trip around the sun! <<Hello Debi>> It has been one week today since I added a Black Brittle Sea Star to my tank. <<Okey Dokey>> My question is, how long does it take for one of these stars to come out and stretch their legs? <<Usually quite secretive.>> I have checked the tank at night, staying up really late with the tank dark for a long period of time and at best only saw a toe peeking from under it's hiding rock. <<Not atypical...though a morsel of food would likely coax it out in the dark.>> It was my understanding this type star would be an excellent maintenance critter and I was hoping a hungry one. <<A good detritivore, yes.>> Perhaps I misunderstood their diet? <<Excess fish food...dead fish... A few shrimp pellets a couple times a week will be greatly appreciated as well.>> I was hoping this star would keep algae dust off the top layer of the sand. <<Mmm, no...not what it "does".>> Will this star eventually come out and keep my sand bed looking nice or do I need to consider another source? <<Not a sand-stirrer...do have a look at the bullets gobies (Phalaena dragon is a popular and hardy bullet goby which is often used for keeping algae off the sand bed).>> I really thought this star was a right choice. <<Still a good choice...but for a different purpose. EricR>> 

Brittlestar 'Stiffening'  9/17/05 Greetings! I wanted first to thank you for maintaining such a helpful site. I have been able to keep my little 20 gallon (don't laugh please) salt water tank up and running - CLEAN - for two years with only one fatality.   <Outstanding> Three days ago I did a normal tank change. My 'pets' and I have a wonderful system worked out between us that has served us well these two years. Since then, my beautiful Brittlestar, Armando Stickyfeet, has been moving around as usual with the exception of his little spines. Typically they are very flexible. Now they are sticking straight out and very stiff. I've offered him his favorite foods - and he stretches up towards it, roams the tank  yet the food is not traveling up his arms to his mouth. I reached in to check him, and he climbed up and checked me out; only this time he wasn't 'sticky' he was prickly! OUCH! He feels like a pin cushion. <Yes> He has always been very active, very curious - I even have a picture of him 'dancing' on my hand.  (I do realize he is not thinking about me one way or the other - no worries - lol) No one else in the tank is acting any differently. My bristleworms are still at two, my hermits, clown and goby - all doing fine as usual. Any information would be appreciated. Sincerely, Winter <Very likely something was different re your new water during the change... this happens... even the municipal water is not a consistent product. In all likelihood your Brittlestar will recover fully... I do suggest (if you're not already doing this) that you pre-mix and store new water between services. Bob Fenner>

Green brittle on the prowl - 3/7/05 Hello... I'm afraid I have a dilemma.  <OK. Let's see what we can do about helping the situation> I recently purchased a green brittle star...  <Uh oh>  ... at the pet store in our town. The shop owner assured me there would be no problem in my tank unless any fish got sick or weak.  <All I can say here is research before purchasing....I know you know this now.>  All was fine for the first few days, he and our mandarin seemed to be getting along well, even hanging out in little areas together.  <Hangin' out is not the word I would use>  My husband and I kept a close watch on them because we were concerned about the safety of our <sic> fish.  <I can only recommend that again, research before purchase. This starfish is well documented on our website.>  Just when we thought things were alright, we caught our brittle star hovering over our mandarin and lowering down as if to eat her!  <Very likely so>  It even spit out the food it had been given about and hour earlier! I had originally wanted a chocolate chip star, but again, the shop owner advised that it would not be a good addition to a reef tank (I only have a pink tip anemone and a mandarin in with the star)  <Well, a chocolate chip star is not a good reef tank addition but with the lack of corals it would likely be fine. Chocolate Chip species are hardy but aggressive feeders, more than happy to mount and consume sessile clams, oysters and all manner of corals, soft and stony.>  My questions to you are: Is this normal behavior for a brittle star?  <Not any brittle star but Ophiarachna. See here: http://www.wetwebmedia.com/brittlestars.htm.  There are many attractive and useful brittle stars. You just happened upon one of the exceptions to the family.>  Should we be concerned for the life of our Mandarin?  <Yes. The brittle star is only the beginning of issues for the Mandarin fish. They need to either be trained to take frozen food preparations or you need to have plenty of live foods either available to you or in the aquarium where the mandarin is housed. A mandarin can decimate a population of amphipods in a small tank in no time.>  And would a chocolate chip have been a better choice?  <Really depends on your long-term vision for your tank keeping. Do your research and then determine your preferred choice of animal> Thank you so much for your help.  <Our pleasure. Thanks for being part of it all. ~Paul>

Something Wrong With Her Brittlestar (10/30/04) Hi. <Hello. Steve Allen tonight.> I have a green brittle starfish.  I think he is sick.  He just sits out in the open instead of hiding behind the coral and he's not going after food like he used to.  I thought he was dead but occasionally he moves his legs.  In fact it looks like he's burrowing his disc in the sand at the bottom of the tank.  What should I do?  Please help.                            Thanks,  Kristi <This does seem like unusual behavior. Have you tried putting a small chunk right  against one of its arms. It should grab it right up. Check your water parameters. Echinoderms need stable, real seawater range salinity and pH. Check ammonia, nitrites, and  nitrates. Any recent additions or changes? Another possibility is an infection. Is its skin and all limbs intact? Hope this gets you started. Feel free to come back with more details.>

Big Serpent Star predatory? II 8/14/04 Well my serpent starfish is not green but brown.  So I'm not sure if I have a rogue sea animal or it just likes to clean up failed fish. <I cannot say either without at least seeing a pic or knowing what species you have. Still... most serpent stars are overwhelmingly reef safe and simply scavenge the dead and dying at worst> Should I remove this star fish or keep feeding it expensive fish?   <at 10" diameter... it is a threatening scavenger to small fishes and some inverts perhaps> Any suggestions? <yes... keep cheaper fish. Anthony>

Lazing in the Tank - Brittle Star >Is it normal for a brittle star to just sit there in the daylight? >>No, it sure isn't. >Are they nocturnal or just lazy animals? >>Heh.. yes, they're usually nocturnal, or at least very shy and secretive. Given their propensity to go fishing I could say that yes, they're lazy, and no, they're not lazy. But for them it's not so much fishing as it is hunting. Watch yours for signs of disintegration. Marina 

Brittle star I have a brittle star or a serpent star. I read in your column that you do not trust them with fish. Could my serpent star be eating my fish? I have several established fish but when I add a new one it disappears. I also suspect a red lobster which I rarely see but know he's in there!  >> The Green Brittle stars (there are other safer species) are notorious for fish-disappearances-without explanation... as well as "reef" lobsters... I would exclude these from a reef set-up. Bob Fenner

Brittle star ambush Mr. Fenner I had an orchid Dottyback who was living inside an empty snail shell. This morning, I found my green brittle star next to the shell with the Dottyback in his mouth. I had heard that some brittle stars can be quite adept at catching sleeping fish, but had not experienced it first hand until now. Should I worry about the brittle star catching other fish? What can I do to keep this from happening again? Thank you. >> Yes. Remove it...  Bob Fenner

Brittle Star Question. A few weeks ago I bought a brittle star for my newly cycled reef tank. I had two damsels and a chocolate chip star in with it. One day I came across my brittle star in full daylight sitting on my highest rock in the tank with all his arms sticking straight out. Also, he was excreting a white liquid into the water.  <from where did it originate? Assumedly from under the center of the body?> He has all his arms and no cuts anywhere. What is he doing and will it contaminate my tank?  <not clear just yet, but no it is not toxic and it will not contaminate your tank unless it is dying/rotting. I assume though that it moved on?> I'm willing to get rid of him because I mysteriously lost both damsels about a week after that. Thanks, Laura <yikes... easy on the knee-jerk reactions, my friend. I'd hate to be a bad child in your house <smile>. One strike and you're homeless! Hehe... I'm sure the starfish did not kill the damsels. And if the starfishes behavior was related at all... it was due to the fact that whatever stressed and killed the damsels could have stressed the starfish first in to behaving so. Since it is a new tank.. have you confirmed that your chemistry is/has been stable? When in doubt, do a water change. Best regards, Anthony>

Brittle Star Question. Thank you for emailing back so quickly about my brittle star question with the white secretion it was emitting.  <my pleasure> I work for a pet store, so I'm pretty informed on a few things concerning brittle stars, but no one at work knew what mine was doing. I finally contacted the seller and he informed me it was a green brittle star (the ones notorious for sneaking up on sleeping fish).  <Arggghhhh! O. incrassata, the wily devil!> I traded him in for a safer cleaner... a hermit crab. So thanks for your quick response! For future knowledge, what was the white stuff my brittle star was emitting? It looked like it was coming from under his disc and he was doing it for at least a half an hour. Possibly sperm?  <possible but not likely eggs/sperm. More likely the product of digestion. Many echinoderms graze aggressively on the rock surface and pick up calcareous material (corallines, etc) to digest the organic material off of them (algae, bacteria, crustacea, etc)... the indigestible material is simply discarded. My educated guess without having seen the event I have no clue and everyone at the shop wants to know! Thank again! Sincerely, Laura <best regards, Anthony Calfo>

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