FAQs about Sea Star Identification 1 Related Articles: Sea Stars, Brittle Stars,  Asterina Stars, An Introduction to the Echinoderms:  The Sea Stars, Sea Urchins, Sea Cucumbers and More... By James W. Fatherree, M.Sc. Related FAQs: Sea Star ID 2, Sea Star ID 3, Sea Star ID 4, Seastar ID 5, Seastar ID 6 & CC Star Identification, Linckia Identification, Sandsifting Star ID, & Sea Stars 1, Sea Stars 2, Sea Stars 3, Sea Stars 4, Sea Stars 5, Brittle Stars,  Seastar Selection, Seastar Compatibility, Seastar Systems, Seastar Behavior, Seastar Feeding, Seastar Reproduction, Seastar Disease, Asterina Stars, Chocolate Chip Stars, Crown of Thorns Stars, Fromia Stars, Linckia Stars, Linckia Stars 2, Sand-Sifting Stars, Wishing upon a star (identification).

Asterina ID  9/15/05 Hi Crew, <Christy> I love your website, very helpful and informative. <Ah, good> Could you help me in identifying this new-comer? <Is a little Seastar of the genus Asterina>   I have a 30 gal  saltwater tank, snails, hermit crabs, 2 clownfish, black sailfin blenny, green  mandarin and cleaner shrimp.  He might have hitched a ride on some corals  that I bought a few weeks ago.  He is smaller than a dime. <Yes... and will not get much bigger> Thanks for any light you can shed on this. Christy <Please search on WWM, the Net under the genus name. Bob Fenner>

Tiny Starfish ID 9/15/05 Hi Crew, I love your website, very helpful and informative.  Could you help me in identifying this new-comer?  I have a 30 gal saltwater tank with snails, hermit crabs, 2 clownfish, black sailfin blenny, green mandarin and cleaner shrimp.  He might have hitched a ride on some corals  that I bought a few weeks ago.  He is smaller than a dime. Thanks for any light you can shed on this. Christy  <It is a small starfish.  They are common in reef tanks and most are harmless.  A very small number of them may eat corals, but I would consider it innocent until proven guilty.  Best Regards.  AdamC.>

Asterina hitchhiker 09/16/05 Hi Crew, <<Hello Christy>> I love your website, very helpful and informative.<<Thank you>> Could you help me in identifying this new-comer?  I have a 30 gal  saltwater tank, snails, hermit crabs, 2 clownfish, black sailfin blenny, green  mandarin and cleaner shrimp.  He might have hitched a ride on some corals  that I bought a few weeks ago.  He is smaller than a dime.<<Judging from the picture, which is difficult at times, I believe you have found an Asterina starfish. Please search WWM for "Asterina starfish">>. Thanks for any light you can shed on this. Christy <<You're welcome - Ted>>

Starfish ID 8/23/05 Hi There: <G'morning> Just a quick question in hopes you can identify (photo attached) what is growing in my tank.  We assume that they are baby starfish (there are about 5 that we've seen), but not knowing for sure is driving us crazy.   Also, just for your enjoyment, attached is a photo of one of our starfish's arms growing a new starfish.  That is sooo cool! Thanks! D. Kelley <Very nice. Thank you for sending it along. Likely a species of Asterina... Please see here: http://www.wetwebmedia.com/asterinafaqs.htm Bob Fenner>

Linckia Starfish? Nope Dear Wetweb Crew, <Sue> My sister purchased the starfish in the attached picture.  She was told it as a rare Linckia Starfish <Uh, no. Please see here: http://www.wetwebmedia.com/seastars2.htm> and purchased it before doing any research. <...>   Her tank is only 2 months old.  She wants to give it to me for my tank and after searching everywhere, I cannot identify it.  I don't want to ad a predator star to my tank.  Is it possible for you to ID from this picture? <Maybe... looks like a Nardoa species (maybe N. pauciforis), family Ophidiasteridae to me>   I can only find information on red and blue Linckias so I hesitate to take this starfish.  Is this a reef safe star? Thank you for you time and expertise. Susan <For a large/r species of asteroid, pretty reef safe... eats mainly micro-organisms, algae... will crawl over live corals though... Bob Fenner>

- ID This - Sorry, I just learned that AOL made me zip 'em. <No worries...> Hello- <Oh, hello.> I am new to marine aquarium keeping and I have found a new creature on the live rock that I (or anyone else I know) am unable to identify.  A picture is attached.  It looks similar to a star fish having one extra long leg. <That's exactly what it is, perhaps a Linckia... seastars have an amazing regenerative capability... this star was probably reduced to just a portion of the disk and the one leg, and it's just been slowly growing back the missing parts. Neat acquisition.> It is about 1.5" in length.  The system has been running almost a month.  The live rock was added during the 2nd week.  Everything seems to be going well, in my humble opinion.  I would like to know what this creature is and if it will harm other organisms. <Probably nothing to worry about... some seastars make a habit of eating bi-valves, but others are less predatory. I'd keep it around.> I find your website very informative.  Thanks for all your help.  LH <Cheers, J -- >

Re: unknown star fish Bob, A while back I asked you about a star fish I had come to me by way of a candy cane coral I purchased. You said you didn't have a clue what kind it was from my description because there are so many different star fish. Well as luck would have it I got a digital camera for Christmas, so here is a picture of the little bugger. So as the man on the game show would say...Bob Fenner...name that star fish   :) Thanks, Robert <Tah dah! It's a Linckia multifora. Please see here: http://www.wetwebmedia.com/seastars.htm Bob Fenner>

Re: Mystery Starfish A friend of mine has a 55g F/LR/SC tank that is a real pleasure to watch. His tank has a number of different mushroom anemones, Xeniids, zoanthids and things I've forgotten their names. No hard corals - not enough light. The place is just a little crowded along those line and I haven't mentioned the fish (though the Pseudochromis will eat out of his wife's hand.) Very recently we discovered that he has several "volunteer" starfish, origin and specie unknown. The largest of these has reached about 1 cm across. Attached is a jpg of the fellow slowly crawling across one of the pieces of live rock. As you can see, despite my poor photography, these asteroids have five arms and a rather significant margin. They are almost reminiscent of a "sand dollar", except that the arm spines are raised and pronounced. The obvious questions are, what is the species and should my friend be scavenging these out? Are they, as I suspect, a danger to their more sedentary tank mates? <Asterina sp. Not an uncommon LR "recruit". Please see here re:    http://www.wetwebmedia.com/seastarf.htm and the related FAQs (linked, in blue, at top). Bob Fenner> Regards, Charlie H.

Pictures for you (Seastar id) Bob, Is there any way that you could tell me what type of sea star this is (I have attached a photo of him)? The pet store told me that they think he was shipped from Sri Lanka, but the guy I talked to didn't seem very sure about it. I'd like to get more information, but it's hard not knowing what type of sea star he is. <Looks like an Echinaster species to me. Am concerned as well (that this may not be a tropical species). Do take a look on the Net with this genus name for a more positive identification. Bob Fenner> Thank you, Christine Marling

Seastar id Thank you for your reply.  The shape and color in general seem to match the Echinaster sepositus, but in the clear up-close pictures of this sea star that I have found on the net, there is a difference between mine and the pictures.  The Echinaster sepositus has reddish purple structures coming out of it's pores, while mine does not.  In addition, the Echinaster Sepositus appears to be bumpy.  Mine is smooth for the most part and has small white/translucent bumps coming from the pores, which gives him the appearance of being fuzzy.  Am I giving the description of any other type of sea star that you know of?  Or do you still think that he is an Echinaster? <I do think this is a different species, but could not make out the surface characteristics you list with the image provided. I did not see a good match with this and Baensch, or my identified pix... do you have access to a copy of Fossa and Nilsen v. 4 of The Modern Coral Reef Aquarium? There are a few members of the family Ophidiasteridae pictured that this animal could be. This is the family that includes the Linckias, Nardoa species. Could you send a close-up or larger image that I might be able to see more detail? Bob Fenner>

Re: Seastar id No, I don't have access to Fossa & Nilsen v.4, but I took another picture of him although he is in a difficult spot to photograph.  I tried to get up closer to him, but my digital camera didn't want to focus on the sea star.  I have attached it along with the original picture I sent.  I hope this aids you in the identification. Thanks, Christine <Only the first pic came through... do take a look on Google (images) of Echinaster luzonicus... does this look like your animal? Bob Fenner>

Re: Seastar id That picture on google of the Echinaster luzonicus has reddish things poking out of it's skin, mine has white/translucent ones. It is almost like the tube feet continue onto the back of him (just shorter) and coming out of the pores of his skin. <Still... could be the same species. Some Seastars have quite a range of color, markings, morphology. Bob Fenner>

Re: Seastar id 3/21/03 Final questions and then I'll leave you alone.  What temperature should  a Echinaster luzonicus live in and what should I feed it?  If this is a cooler water species should I run him back to the store screaming and yelling? <there's a brief but succinct report on the breeding/husbandry of this star on Seascope in this archive: http://www.breeders-registry.gen.ca.us/Reprints/SeaScope/v13_fall/star.htm also, see page 216 of the Indo-Pacific Coral Reef Field Guide (Allen/Steene) for an image to compare to. Best regards, Anthony>

Unknown Starfish Hey Bob, <Steven Pro in this morning.> I purchased a candy cane coral Sunday evening and when I got ready to put it in the tank I noticed what I thought was some sort of a sea slug on the base of it. But in looking at it closer it turned out to be a star fish, one I have never seen before. This little guy is only about 3/16 across arm tip to arm tip, however it's one arm is about 1/2 long by it's self. The star fish is blue in color, but the long arm has a almost snake skin pattern to it. Any idea what the little guy is? Thanks, Robert <No, but he sounds really cool. Can you get a picture and send it to us for further help? Something in the 400 KB range would be nice. -Steven Pro>

Little Dingy White/light brown starfish What are the little (1/4 inch) brown starfish that are so abundant in my 180 gal reef tank?   <likely you have an Asterina species. Do use this name to do a 'Net search for photos to confirm. They are prolific and actually useful for eating diatoms (algae). Some people culture these to feed the magnificent Harlequin shrimp which can live well and breed in captivity if provided a natural diet of sea star tube feet. As you have noticed, they can reach plague proportions. Some say they can eat coral... this is very rare. Aside form being prolific, they are quite useful. SPS keepers just like to use them as an excuse for why their corals are dying ;) These sea stars are merely scavenging the necrotic tissue of an already dying/infected coral. Best regards, Anthony>

Creature ID Just thought about that too... Ok here it is.. Little white bugger to the left. <despite the image quality (I know its tough to take a good shot). I can ID this sea star as an Asterina species. They have a mixed reputation. I personally like them just find. Find them to be harmless and mildly irritating at best. They are very good at eating brown algae. They also breed prolifically. This irritates some people and they call them a plague. In rare cases they will nibble coral. I have literally had thousands of these sea stars grown in my facility and home tanks, and I've had more coral than you could count in with them in ten years... only once did I find one star that seemed to nibble on a soft coral. No harm done.> Also I found today I have another hitchhiker.. well it looks like a big hairy spider from a distance, but up close it a crab of sorts.. I'm trying to snap a shot of him too, but he's camera shy! :-) <bait him with smelly frozen food at night. Hairy can be dangerous to corals... in fact: almost no crab is reef safe. I don't even recommend reef safe hermits for most reef aquaria. They are almost all omnivores> Thanks for the help (AGAIN) :-) <best regards, Anthony Calfo>

Teeny Sea Stars I have a question about some teeny starfish I recently acquired-- they are about 4 millimeters across, most are missing limbs and I have been told they only get to the size of a dime and multiply like crazy. I have been trying to find out their species and nature...we have a brand new reef tank, 7 weeks old. Thanks for your help, Lizzi <I would agree with all of the above. Look up Asterina species here in our WetWebMedia.com archives and beyond. Any references you see about them eating coral are mostly bunk in my opinion. Very rare. They are only a nuisance for fast propagation. Great algae eaters and little harm else wise. Best regards, Anthony>

Snail and star identity Hello all, I am having no luck finding the identity of a snail the hitchhiked on my rock, as well a sea star.  I have looked at e-tailers and this site with no luck.  Can you give me some more suggestions that can help in the search? If not, I will email you a couple of pictures to see if that will help. Thanks, Kim <hmmm... depends on the local of the rock. Atlantic or Pacific? Seek Humann's references if Atlantic (Reef Creatures)... Pacific will be more challenging/ Perhaps a photo will be best for all. Do look up Asterina species for the sea star by the way. A common incidental. Best regards, Anthony>

Tiny Little Starfish Hello all, or rather, whoever ! I had moved my 55 gallon tank a month ago and everything is pretty much broken down. Various fish are in different tanks all through the house, all inhabitants are doing great in their little vacation homes. My concern is this: The main tank which just has a lot of my live rock and live sand in it is infested with tiny little whitish, bluish starfish. I have had a few of these guys from the beginning but never so many like now. The tank has about 40lbs of live rock in it, about 4 inches of live sand, lots of brittle stars, macroalgae, etc., but no fish. I have read some things on these little guys, and I know they supposedly eat coral, don't have any of that, so it doesn't really matter (but will in the future), but I just don't want them in there and refuse to kill them. Is there some fish or such I can get to eat them? Do you know of any damage they may cause? <Without a picture, I can offer you a few good guesses. First, I bet the starfish are harmless. They allegedly eat coral, but you have none and they still reproduce and thrive, so I think they are probably eating something else. Secondly, they are reproducing without fish in the tank. Again, it makes me think they are eating something that the fish would normally eat and compete against them/starve then down in population or whatever fish you have may eat some of the starfish. I would not worry about them at this point, but do try to make a positive identification. Take a look in Julian Sprung's book "The Invert Guide" and Dr. Shimek's "Key to Identification" found on his webpage.> Also, I made my own protein skimmer (countercurrent flow, airstone driven). Since the filter system is broken down right now, I was thinking about changing it to Venturi driven. Is this more trouble than it's worth? <Generally less maintenance than CC air driven models, but far more difficult to DIY.> Do these things really run better than with airstones? <Very debatable. If you are getting good production now, I would be inclined to keep the current unit.> I sure go through a lot of airstones and thought it might even be more cost efficient over time. Whatcha think? <Airstones are pretty cheap. It would probably take years to recover and money saved in airstones versus the pump and Venturi valve to run the new DIY skimmer. Upon rereading, I am not sure you wish to DIY. If not, I would look through the FAQ's on skimmer selection for various recommendations for various size tanks and applications.> Thanks for all the advice, and have a good weekend, Jana <You are welcome. -Steven Pro>

Nuisance sea stars (Asterina) Hi, and thanks for your last reply on the length that I can keep mixed Kalk. I am now becoming concerned with the eradication of the dreaded tiny starfish that can get up to the size of a dime that I have had in small numbers in my tank for approximately one year.  <I assume that they have not eaten anything desirable, but that they have simply grown to a nuisance population?> I continually find them everywhere and have removed upwards of 200 from my tank over the same time period. The starfish have only been on one side of the tank but are now migrating to the other and I am worried about my SPS corals on that side of the tank.  <my friend... at these numbers, if the species hasn't eaten a coral yet, they are not going to. Most aquarists never have a single problem with this species... only a few honestly do. They are just a plague... not much of a predator> I have a 180 gallon. Will the Harlequin shrimp take care of these if I can find one or two?  <Yowza! This is an obligate feeder. It may eat the stars... but what happens when the stars are eradicated? Are you willing and prepared to buy live starfish monthly if not weekly to keep the shrimp (s) alive? I would never recommend that you simply put a Harlequin in this display for this purpose alone of even primarily. Harlequin shrimp need specialized and direct care> Would I need to keep two or more for the shrimp to feel at home? I don't think I have any fish that would hurt the shrimp. I do have emerald crabs which have never hurt anything that I have so far.  < "so far" being the operative phrase in that sentence... wait until they grow to sandwich size and the cat goes missing> Would I need to remove my sand sifting starfish or wouldn't the harlequins bother them?  <the Harlequins will likely bother your other sea stars> Any other ideas for ridding my tank of the pest starfish?  <dedicated ,manual extraction if they must go... else they are truly excellent algae eaters from the glass (and rocks). You will notice once they are gone> Thanks again, Jeff <kindly, Anthony>

Starfish or Not? I have a reef tank....lots of coral....few fish. Last night on the glass, there was what appeared to be a baby starfish.....although it has 7 legs. <one of the wonders of reef tanks/live rock... many fascinating microorganisms> We took it out of the tank since we recall hearing that this is a potential risk to the corals..... <please don't make a habit of doing that my friend... the overwhelming majority of creatures that you find will be harmless or likely even beneficial. In fact, even the "worst" nuisance animals can easily be controlled via natural predation. My advice is to leave all alone... let it grow, let it grow, let it grow :)> do you know anything about this? <could easily be a seven legged starfish... > Heather <While you are waiting for the WWM "Reef Invertebrates" book to come out <wink>, please check out the following sites for such oddballs http://www.reefs.org/hhfaq/pages/main_pages/faq_rock3.htm http://www.rshimek.com/odd_critters.htm kindly, Anthony>

Identity of Starfish Hey Bob: I have been asking you for help and advice. And you have given both willingly. Thank you. I thought this time I would share an interesting story and maybe you can help me determine the identity of this starfish. A few months ago I bought a starfish from a LFS and put in into my 55 gallon reef and fish tank. The LFS said it was a red reef starfish, it has six legs, but I cannot find any pictures or reading on this starfish. About 2 weeks after I put the starfish in the tank I noticed 1 of its legs had twisted and started to tear off. Not knowing what to do I left it to it own accord. A few days later the leg was gone and another leg started doing the same thing. A few days later it fell off and another leg started doing the same. Every other leg was falling off this animal at about 1/2 way up the leg. I was furious. I went to testing the water. All was well, except the nitrate was at .10. I started grabbing buckets and salt and parasites medications and rubber gloves preparing to do an emergency water change and to pull the starfish out before he crawled under a rock and cause me to have to pull all my rocks out looking for him big hassle). As I was making up swear words I looked down and seen one of its legs moving close to my bubble coral until it moved out of sight. Surprised I looked at my wife she had also spotted the other leg at the other end of the tank. I calmed down and laughed a little. Not knowing for sure what was going to happen next I put up all my emergency stuff and left him in the tank to see what happens not normally the best idea). The starfish has long since lost the 3rd leg and is now regenerating new ones, you can see the tips very well and each of the three legs are now growing 5 new tips and resembles a starfish rather than a red slug. WAY COOL. More description of the starfish: Red with some dingy red areas blotchy Skinny like a Linckia except legs are rounder and more pointy Six legged when their all there (haha) about 4" across  Thanks again for all the help K.J.  <<What a planet! I'm not leaving! Well, at least not willingly, and not for a while... Yep, strange goings on like this are what keep the hobby more than interesting. Am familiar with such reproductive strategies. May be this is a Pentagonaster duebeni... they're red, blotchy, but have more flattened top to bottom, with rounded edge legs like Fromias... Or, maybe it's a Luidia ciliaris; these often come with six legs... instead of the typical pentaramous/echinoderm array... but it has side-spiked legs that I'd imagine you would've listed... Or perhaps a Mithrodia bradleyi, though these mainly come out of Mexico... Or Echinaster sepositus... but they're coldwater... A commonly offered variety, Protoreastor lincki fits the description... sort of looks like the Choc. Chip Star of the same genus, but red, with red protuberances... as do a few of the little Seastars of the genus Fromia... could be a Hacelia, Leiaster, even a real Linckia... As you can see, there are MANY possibilities... Take a look through Baensch Marine Atlas #3.... and I'll bet you get close. Bob Fenner>>

Little critters Hi Bob Today I went to change the little Chemi pure bags in my tank and discovered a bunch (50 or so) of these tiny little white starfish. What strain are they?  <Strain? Impossible to tell from where I'm sitting... take a look through Baensch Marine Atlas v.3 maybe... about the most complete collection of images, information on aquarium species of Seastars> are they coral munchers? or are they ok to have in there? They are very very bright white, as their color is so bright , I thought that they are probably night time dwellers, I think). As always great thanks, and have a good day! <Hmm, maybe take a look/see at the Seastar article and FAQs stored on the www.WetWebMedia.com site... a friend (Tom Walsh) had a common small star I took pictures of that I've seen other people keep with impunity... Maybe your species is the same... Bob Fenner>

Little critters Hi Bob I looked all over your site a still can't find anything about the tiny little white starfish I have been finding in my reef tank. <Hmm, maybe those pix didn't make it there quite yet...> These little critters are under both Chemipure bags that I have in my tank. I only have one brittle star in the tank. It has been in there for about 4 years now. I don't see how it can reproduce with just the one star. The little ones that I'm finding are a bright white in color, and look like a regular brittle stars. Do you have any idea of what kind they are? <Not anymore than your description... but very likely they're not a problem> All of them are about a quarter of an inch to a half inch in size. They all have five little legs, and are completely bright white. If you can be of any assistance please let me know. As always, thanks. and take care.