SnailIDFAQ3

FAQs about Marine Snail Identification 3

Related Articles: Gastropods, Sea Slugs, Mollusks, Abalone,

Snail ID Hey Bob/Pete Its a little tough to ID with that bugger covered in coralline <G> The spike sure is distinguishing if they all have it (not an anomaly with this one I assume?) I don't see how this is/could be a conch species... really does not look the part to me. IMO... it looks Nassariidae. Its behavior and shape (and what little pattern there is to the shell still resembles the bands of mud snails variously). Bob... have you sent this image to Marty B at Tideline? Do you think he might recognize it? Anthony

"Red Footed Conchs", prev. snail ID Hi Bob, This is John Phillips at the Abbey. How goes the struggle? <Fine John, great to hear from you. I trust you're still playing the harp, keeping things going there with Marty.B> Sorry for not getting in touch, but I'm always behind in just about every facet of my life & certainly not the efficient correspondent that Marty is; however, I am being somewhat punctual and efficient regarding this e-mail because it involves taxonomy about a particular shell that I am familiar with. The common name of your shell is "The Thorn Latirus", which stems from the very gaudy and menacing spine/thorn that grows out from the bottom of its outer lip. It is a member of the Molluscan Family Fasciolariidae and goes by the 'handle' Opeatostoma pseudodon and was first noticed and officially/scientifically described by a chap named Burrow in 1815. It hails from a broad range of miles stretching from Peru in South America north as far as northern Baja Calif., W. Mexico. Lives in shallow water and prefers haunting stony corals, rocks, and boulders. Not a good thing to accidentally kick with the end of your big toe kissing the menacing tip of its thorn!! Not poisonous however!! Hope this trivia proves useful & always a pleasure to provide same. Best to you and your lovely wifelet & we shall get together again soon for some chuckles. Cheers from TIDELINE JOHNNY <Outstanding. Thank you John. Will archive your response with the pix. Best to you. Bob Fenner>

Mysterious slugs in my salt water tank 6/15/04 Hi there, <cheers, dear> I had a couple of questions. I've had my Nano Cube 12 gallon tank for about half a year and everything inside has been doing very well. I do weekly water changes and check for pH and salinity on a regular basis. <excellent to hear... I run a very successful Nano reef of my own with weekly water changes :) > However, this past week and half I noticed a mysterious yellow slug-like thing in my tank. I didn't pay too much mind to it, but the past few days my daisy coral hasn't been penning up at all. I'm new to this saltwater tank thing, so I'm not sure if it is dead. This morning I noticed that there was not only one, but three, slug-like things in the tank. They are all almost an inch long - could this be the reason my daisy coral is having problems? <yes... almost certainly. Nudibranchs like this are not uncommon at all... and can be devastating (please do use a quarantine tank for all new future livestock to screen for such pests and predators)> Where are these slugs coming from? <lack of QT... entry with live rock, new coral, snails added, live sand.... anything wet you've added recently> Any help you could give me would be wonderful! Melissa <remove them manually, and rest assured that they are likely coral specific and will leave most other corals in your tank alone. There is a common dirty yellow species frequently imported and so-called "Tritoniopsis" or "Tritonia". We have a couple of references to them here: http://www.wetwebmedia.com/seaslugfaqs.htm and here: http://www.wetwebmedia.com/nudifaqs.htm use the "Find" word option from the toolbar on your browser (under edit likely) to find the location of these words specifically on the page. Best regards! Anthony>

Cowry ID 5/2/04 Good evening/morning! (it's 4am) <cheers> Hope all's well. I have a quick question, do you know of any website/book that has pictures of living cowry snails. I looked online, but all I could find were pics of cowry shells (thoroughly useless!). I have a little one I would like to id. Any help is appreciated, Morgan Mok <I suspect it will not be hard to ID... but it would help if you know what ocean it came from to narrow the search. I'm not aware of any "Live Cowries of the World" book ;) For Atlantic species... Humann's dive book series is excellent. From the Pacific, there are several great references. Most/all of these field guides can be purchased from the excellent natural history bookseller seachallengers.com kind regards, Anthony>

Bad decisions... wrong species, right admiration 5/27/04 Well, I'm not sure what sea this cowry comes from. I got it from a friend's tank because I'm an invert lover and I think cowries are really cool. ;] <fascinating yes. Do check out our coverage of gastropods in "Reef Invertebrates" by Calfo and Fenner too> I can give you a basic description and see if you can make anything of it. <nearly impossible from a text description. A photo at least would be helpful> It's about an inch long, the shell is creamy white w/out any visible markings. The mantle is white w/ dark purple circular spots all over it. The foot is white/translucent w/ the outer perimeter being purple/dark magenta colored. I'm not too sure what it eats, maybe algae maybe snails. Who knows? ;] It is nocturnal for sure. <It never ceases to amaze and disappoint me that people bring pets into their home without knowing what they eat/need to survive> Thanks for any info you can give. Morgan Mok ps: Do you know where a person can get electric scallops? ;] <they are near impossible to keep for anything that approaches a natural lifespan in captivity... unless you have figured out a way to magically culture bacteria, nanoplankton and other necessary plankters> Also, do spiny scallops/oysters (can't remember the name) need temperate waters in order to survive? Thanks! <Ughhh... if you are referring to Thorny Oysters... they are near impossible just the same. These azooxanthellate bivalves are some of the most difficult reef invertebrates to keep alive in aquaria. They slowly starve over a period of weeks to months categorically (very few exceptions). Please be a responsible aquarist and avoid these specimens. Read more about why on our free content website, wetwebmedia.com, or our last book if its handy. Anthony>

Woops! >Mr. Fenner, >>Marina today, Bob is in Egypt ogling mermaids. >My apologies for the repeated interruptions, I have a snail that I cannot find on WWM. Please see the attached (albeit terrible) photo. >>No photo is attached, mate. Try again, and please make it about 300 pixels to a side, and no larger than 200-300kb if possible. >It is relatively flat with only a mild volcano appearance. It grows rather rapidly and has a hole at the top, if that will help any. Thank You very much for your time. Daniel >>I'll have to let you give this one another go, my friend. Marina

ID Snail/Slug ?? (with pictures) 4/6/04 Hello crew, These two guys came with two soft corals I recently picked up. I noticed them just before putting the pieces in my tank so I took them off and have been trying to figure out if they are friend or foe. My tank has all soft corals (polyps, pulsing xenia, zoos etc) <Good to be cautious! Unknown hitch hikers are a good reason to quarantine.> One has a green "hump"/shell on his back and the other has a hump but it is not as green. Another one was able to get in my tank and I have yet to find him/her. <Your pic is a bit fuzzy, but the critter is almost certainly Stomatella Varia (AKA "cap snail"). If you do a Google search, you should be able to find a very good pic to compare to.> Good or Bad? <One of the very best critters to have in your tank, IMO. They are nighttime algae grazers, harmless to all other animals in in many tank they are prolific spawners that provide a lot of coral food.> Thanks again for all your help.
<It's always a pleasure!>

Can you please help me identify this snail?? today I got some corals for my reef tank and on one of them is a snail about 1inch or so in shell length. he has a white shell that looks like a conch shape. it has a bright red body and yellow spots. I looked online and its not a red foot. the only other snail I have seen like this was on the blue planet series on the discovery channel and it was called a saddle conch I think but it eat snails and inverts. can you tell me what this snail is? I just hope its not a saddle conch <I'm not sure how I could possibly ID this for you my friend without a description or picture (preferred). If it looks like a conch though, then it is not likely to be an algae grazer and may very well be predatory. Anthony>

Nassarius? or Conus? Predatory 3/22/04 Greetings Crew, <cheers> A little help with an ID. I was sold this (picture attached) as a Nassarius snail, but it is about 11/2" long and I watched it consume a 1" Astraea snail, shell and all and take it underground, granted I think the Astraea was dead anyways, <hmmm... not necessarily. Many gastropods are predators on others> but I am also missing a 3" Blue Mandarinfish, I haven't seen him in three days? I have or had two of these supposed Nassarius snails (I've only seen one for about a week), a dozen small Hermit crabs, a sally lightfoot crab, and a sand shifting snail. <it is clearly not a Nassarius... and the radula at the front end indicates that it is a meat eater... predator of some sort> Also these guys go under the sand bed pretty quick with only a small tube sticking out of the sand bed, and pretty much stay there, unless they are "hunting", one did come out one other time, crawled up to the top of my tank glass leaving some stringy slime and then back down and underground again. Any Ideas? Thanks for your help and your site. Sincerely, John <this is clearly not a reef-safe snail to me... although I'm not sure what species it is (not too hard to determine with better pics or your time browsing through shell-collectors web-sites for IDs. Nonetheless... some killings could have been avoided if you would have/will put this and all new creatures into a proper QT/isolation tank first before adding them to a display - very dangerous. Some such snails will selectively kill all of the Astraeas in mere days/weeks. Please do review/read our articles on the importance of QT and correct ID before buying my friend. This snail looks nothing like a Nassarius and gives/gave no reason to be suspected as such/safe. Best of luck! Anthony>

Re: Conus on 3/22/04 WWM FAQs Anthony: I saw the picture of a snail someone had mistakenly thought to be a Nassarius in today's FAQs. You suspected it's a Conus sp. It sure looks like one to me, too. <actually, the person writing the query thought it was a Conus sp. if not Nassarius... I do not believe it is either, but did not have a good reference handy to peg the shell. I suggested the chap look it up on a shell-collecting web-site (those guys are so good! at obscure shell IDs). Nonetheless, I did say/recognize the shell as a predatory species with its modified radula (proboscis). Likely just a predator on other gastropods... small fishes at best> If so, is it not potentially deadly to humans? <there is a "textile" species of Conus that is fatal to humans. I am not aware of a single recorded sighting/killing of an aquarist by this snail though. Afflicts divers and coastal human activities> I sure wouldn't want one in my tank and would strongly recommend extremely careful removal to avoid any contact that could result in a lethal sting. The question would then be what to do with it. <contacting a public aquarium for use as live... or again, one of the shell collectors to put it to some kind of use would get my vote, rather than simply destroying it> Am I mistaken about the danger of this specimen? Steve <quite correct my friend... those textiles are scary lethal they say. May account for some drownings by swimmers. Anthony>

Being and Educated Consumer 3/23/04 Hello Anthony, and or crew, <howdy!> Thank you for your response to my last question. <always welcome my friend> The Astraea that was consumed was lying on the sand bed for three days, I thought I would leave it for the hermits, I am new at this, but have learned that the Astraea is a good algae eater, but it is also quite clumsy, <hmmm... no harm in being new. Welcome to this wonderful hobby! As to the Astraea being clumsy, though... not really. Its more a matter of being put in an unnatural aquarium/system - point blank: they do not occur on/near soft sandy substrates in the wild (other gastropods do and are better suited of course). As such, when they fall to the sand, they are poorly adapted to right themselves or return to familiar hard substrates. They are excellent algae eaters, but for your sandy tank, it would be better to use Turban/Turbo species form the Pacific... or better still...tank raised (and easy to reproduce at home) Trochus or Strombus species like from IPSF.com... or glean some free Stomatellid or Cerithium snails from a member of a local aquarium society> also I did try to research the Nassarius snail, and some pics I seen had the same little scope thingy sticking out of the sand, <yes... they do have a modified radula/proboscis which indicates (in any snail) that they are not algae eaters. In the case of Nassarius... they are harmless detritivores (still no algae though)... but most such snails with that "schnoz", are predators> I did notice that the shell was different, but I didn't think that the shell told all, <the shell does tell all, my friend> because I heard of a giant Nassarius, <just a silly trade/marketing name <G>> but have been unable to find photos... One thing I don't understand is how a QT could of helped, <it would have illuminated for you an animal that wasn't eating algae or dead meaty foods and indicated to you that it was a predator before it started killing things in your display. QT is to be used for so much more than disease control/screening> I have one set-up and ready to go, but what would the snail have shown during the QT process that would have helped? <I'm grateful to hear that you have a QT ready my friend. Please do remember one rule if none other... everything "wet" goes through QT for 4 weeks without exception (plants, algae, sand, rock, fishes, snails... everything!) and you will have peace of mind and a much more successful tank/enjoyment of the hobby... not to mention fewer deaths/illness in the long run> The ID was my problem, I was told that Nassarius snails are good, I went to the LFS to buy some Nassarius Snails, I would never of thought they would sell me something as something else, <it is natural to feel/believe this indeed... but caveat emptor. Being an educated consumer is the best/only way to buy live animals. Know what it is, what it eats/needs and how big it is before buying any live creatures> that lesson learned, but on the other hand I did search for Snail ID's on this site, and got some question and answers, but no pictures of Giant Nassarius snails, or any snails that resembled my snails, <understood... yet for all of our best efforts and the enormous size of the site, we are not all-knowing <G>> believe me I have been spending hours reading articles on your site, which is good, because I'm learning a lot, but it is hard to remember everything I read, because there is so much, I want to be a responsible reef keeper, and I am trying to do what's right for the life in my tank, all I want is a good clean-up crew, and everything I have tried has failed, the Turbos I bought landed on the bottom of the sand bed as did the Astraeas , and that was with drip acclimation, <'twas the source/animals... and not the species that failed you here. No worries... do try the species again if you like... or better still, the Strombus or Trochus species [note: avoid most Strombus snails like conch that get too large (over 3")... and stick with the small species like those at IPSF.com]> the Nassarius snails well you know, and now I have a dozen hermit crabs, which I was told is reef safe, and now have read that they could become a problem, and one sand shifting star, that I have learned eats the live sands good stuff, <yes... and that starfish needs 100 gallon tanks minimum to have a chance at surviving anything close to a full lifespan. Yours may starve... do consider removing> I have no problem with chemistry, I have a 75 gallon reef ready tank, with about 99 lbs of LR, and a 5" DSB with a sump, and a SeaClone skimmer that I also know is not good (now). So I have a 75 gallon reef ready tank with 99 lbs. of LF, a 5" DSB of aragonite LS, a protein skimmer that is worthless, a sump, good chemistry, good flow, a dozen hermit crabs, and a sand shifting star, What should I do now? <no biggie... it will be fine. You can simply adjust or increase water flow and improve skimming alone and that will take care of most any nuisance growth you will encounter by optimizing nutrient export> I don't mean to sound so sour, but $3000.00 into a hobby trusting some people that should know what they are selling (LFS), and some mistakes on my part when I want to do good, I am just plain hurt and frustrated, Please help me right this ship! Please!! <consider it this way, mate: you would not buy a $3K car or other big expense just on the first salesperson's word and good name, right? You ID the car, make, history... check under the hood, ask friends for opinions (people that are not trying to sell you stuff ;)), etc. Just be an educated consumer across the board. Things failed here because you bought the snail without a correct ID, and you did not QT it ta' boot. We have all made this mistake and most of us learn from it. You will too. But that isn't the LFS fault. To some (large) extent, the burden is ours re: information gathering to make informed decisions.> I should also note that my tank has been up and running since 2/10/04. <let me strongly encourage you to find a local or regional aquarium society to visit and perhaps join my friend. Fish clubs are some of the very best places to get free, accurate and unbiased information from people with shared interests as you and no desire to sell you anything/no bias. In some cases, the info is far more reliable than what you can find on the Internet (random unqualified postings). Do a keyword search of your home town/region for clubs and also check the big message boards like ReefCentral.com which have long lists of clubs/forums. Best of luck! Anthony>

Re: Nassarius? or Conus? On a good path 3/23/04 Anthony and crew, <howdy!> Thank you so much, you are completely right, and you gave me a ton of information that is going to help, I have been trying to be an educated Consumer, my problem is I was being educated by the wrong people, <truly understood, my friend... most of us have had this experience.> but that has changed, not only have I found you, but I have also bought your book, and the Conscientious Marine Aquarist, along with a few more, and I'm joining a local club, and have joined a couple sites... <excellent... all wonderful to hear> So I'll be taking a step back and reading for a bit. <one of my fave sayings - "Its greater later". Yes... agreed> I took the two snails to a LFS I found that has a consultant from Shedd Aquarium, I might have found a good LFS, anyway, they think that they were a type of olive snail and took them for me, and gave me some true Nassarius snails and two Turbo snails, what a difference in what I had and what a Nassarius is.. wow! <heehee.. yes. Indeed> And I also got rid of the Star.... Thanks for your help! <all the best to you and your enjoyment/success with the hobby and beyond. Anthony>

Snail ID...sans pic 3/19/04 I have looked through most if not all of the snail pics and links offered on this sight, and still can't ID this little one. I have no way of getting a pic. to you, but I figured it couldn't hurt to ask any way. It is about 1/8 to maybe a 1/4" in length. The shell and body shape are identical to Oliva sayana Ravenel (eyes mouth and all). But, the color of the body is completely white, and the color pattern is like the pattern found on Marginella plumiosum or Glowing Marginella. However, the color on the pattern is different. The background color is white but instead of the striping being a light yellow it is a tan color with the last band at the rear being a dark brown. It came out at night when I first saw it and caught it. Any ideas? <no way of saying for certain without a pic at least/minimum, let me suggest that you browse the books and internet sites for shell-collectors. A wealth of information there> Also that same night I noticed my Cerith snail egg squiggles were gone and noticed that amongst the pods on the glass were many tiny white round spots attached to the glass. The outside of these spots were covered with several clear thread like projections, spaced along these threads are 3-4 small clear circular capsules. These threads are irregular in placement and length and are easily moved about by the current. So far I can't tell if these little critters can move, they seem to still be in the same place I found them last night. Some of them are larger than others and some have more threads on them. Are these pods as well or other beneficial critters? Could they possibly be snail larvae? <again... very sorry, but a gross description simply doe snot help us here my friend. We'd just be guessing randomly> The Cerith snail eggs were only laid maybe 3-4 days ago. I have Cerith snails, 1 fighting conch, several smaller snails I have Identified but have forgotten the name of. A colony of Zoos, a Linckia, two yellow sea cucumbers (they are going to a new home) DSB, LR hitchhiker critters including a small red hermit crab I'm trying to catch, and a purple feather duster. I also have many little spiral like white hard tubes on the glass I forgot their name as well. <these are Spirorbids... described with so many other worms in our new book, Reef Invertebrates (Calfo/Fenner)> They have little feather duster like fans that filter the water, tube worms come to mind. Any way any help is appreciated. Shauna <best of luck! Anthony> Mystery snail and starfish question Hello all! <Steve Allen> I have a mystery snail in my reef. What kind is it? It's not in any of my invert books. I removed it tonight, and moved it to a tank without any complicated rockwork, so I could find it again if I needed to. <Does it bury itself in the sand? Looks like some sort of Nassarius (or similar subsurface) snail to me. Generally harmless cleaner of sandbeds. Search WWM & other web sources for pix & info.> Also, do you know if Linckias are known sponge eaters? It seems that's all my orange Linckia likes to eat. <Well then yours is, right? The are generally opportunistic scavengers. No real surprise if it eats sponges.> Everyone I know who has tried one has seen it die fairly quickly. <Yes, which is why I think they should not be sold. Lost a few myself before switching to Fromias> So far, after about a month, mine's still looking chipper. Could it be the sponge diet? <Perhaps. A month is a good start. Kept your water clean & stable and maybe you will succeed where most fail. My fingers are crossed for you.> Thank you! Vicki Madison, WI <A great town. I travel there twice per year on business. Next trip in 3 weeks.>

Limpets to the left of me, jokers to my right - 2/16/04 Hi guys, <Hey Larry> I need help identifying a living creature I found in my reef tank. <Hard to do without a pic> I just found an animal that is about 1-1.25 inches in diameter, that is black in color and flat as paper. <OK> It has a hard 1/2" long by about 1/8" wide white stripe down the center of it, that feels like shell or bone. <Shell.> The rest of the animal is slimy and soft and ovoid in shape. <It is a limpet. Scutus unguis or more commonly called the "shield limpet"> I think it has 2 small antennae at its head and it is very slow moving along my live rock. It sort of looks and feels like a Chinese black mushroom if you are familiar with them. Please help, I want to know if it is reef safe. <The common belief is that they are not reef safe. I however have raised on from a juvenile with no effect on any coral or other living animal except for the algae he seems to eat off the acrylic and live rock. I will leave it up to you research a bit more and see if you feel like you want to risk keeping it. I don't see a problem with it, in my experience ~Paul> Thanks, Frozen in Minnesota, Larry.

Unidentified snail - 2/15/04 Hi, This is Jonathan I have a fairly important question. <They all are, my friend> About 12:00 last night I was flashing around in the tank and I noticed a snail moving on my live rock and it was moving pretty fast for a snail so I examined it and it's a snail that I have never seen before. <So this is a snail you did not purposefully place in your tank? Very cool> I examined it and it looks like a snail except it has a tube that comes out in front of itself to feel around and inside is it's mouth. <That is a proboscis. It is used for feeding.> I put it in a cup with a piece of shrimp and it started eating it <Sounds like it could be a Nassarius snail. A harmless scavenger of meaty items. I would definitely look through the internet and see if you can't identify it.> Recently I have had several snails and hermit crabs die I was hoping you could help me out. <Well, the other hermit and snail deaths are likely unrelated, but until you positively id the specimen, there is no telling what it is or what its possible threat to your inhabitants are. Also, I remember reading some of your inquiries lately and I seem to remember your tank being a fairly new setup. A newly setup aquarium can and will attribute to invertebrate death sometimes.> Sorry I can't get you a picture right now. <either a picture or some identity from another source would be ideal. Thanks for being part of it all. ~Paul> Thanks Jonathan

Prehistoric worm...errr...??????? 1/30/04 Hello, Thanks for taking the time to look at my message. I have been to countless research and identification databases and so far have come up empty. I believe the thing in the attached pictures came in with some live rock although it may also have hitchhiked in with any one of several large coral colonies. Any identification help you could assist me with would be appreciated. <Such hitchhiking is certainly a common experience, and the possibility of bringing in destructive critters is a great motivation for quarantine!> It lives inside a rock and comes out to feed on sponges and algae. <How do you know this is what it is feeding on? Have you observed it feeding? Have you observed it at night to see where and what it forages? Abalone for example, are known to wander widely at night only to return to the same daytime resting place.> I have never seen it completely out of the rock but I have seen about 6" of it. I would estimate the head to be approx. the size of a half dollar and the main body to be approx. ?" in diameter with a rounded corner square shape. It has spines/ horns the size and shape of a rose thorn that run along the body to its head where they almost de-evolve into what looks like soft open tissue the shape and size of a spine/horn. Hopefully the picture will explain it better. <Six inches!! Wow! If this critters eating habits were destructive, it would probably be quickly obvious. It looks like the middle section of it's back are separated into "plates". If so, and they are leathery, it is a Chiton. If it is a single, hard calcareous shell, it is a limpet or other mollusk. Kudos on finding this unique critter! Please do continue to observe it carefully. Such a large critter could do some serious damage if is or becomes predatory.> Thanks Again, Mickel <Best Regards, Adam>

Neat pic for the reef obsessed Hi all, <Adam> I moved a message with the subject "Prehistoric worm...errr...???????" to the images folder. I thought that the reef/invert junkies may appreciate it and that it may be a good one to save for future reference. consider particularly that the sender reports the critter to be in excess of 6"! <Wowzah! FYI I or Marina (or Jas or Anthony) save the incoming graphics on our active desktops to place... later... to save space on the WWM mail server> I also wanted to get some confirmation from the group... Although not a very typical specimen, I was fairly certain that this critter is a Chiton, but advised the sender to determine if the "shell" was composed of multiple leathery plates or a single hard calcareous shell to rule out limpet. <Does appear to be a Polyplacophoran to me as well. Bob F> Adam

Help w/snail ID, if you would. 1/13/04 Evening guys :) <Hi Leafy!> This snail is about a half inch or so in length. The coloration is a tan/brown base with 3 lighter yellowish/white stripes on the shell, with a thin white strip near the mantle. This white stripe has 3 brown dots in it, in line with the stripes on the upper part of the shell. I acquired 3 of them in my bag of Nassarius snails, and although they are indeed not, they have very similar behavioral traits (burrowing in the sand, emerging when tank is fed). They also appear to share a similar feeding structure, so I am assuming they are related to the Nassarius. Any help in this identification would be greatly appreciated <Sorry to say that despite that wonderfully detailed description, a certain ID is not possible. Snail ID's are made largely on shell structure, not coloration/patterns. The primary part of the shell used for ID is the operculum (the opening). Nassarius have a distinctive groove in this part of the shell where the siphon passes. If you look for the presence of this groove on the majority, you can compare to the oddballs. Some snails that look similar to Nassarius are predatory, so do keep an eye on the "strangers". Adam>

Mollusk ID - Limpet 1/7/03 Hi Guys and Gals, <Whassup G-money?> This thing appeared the other day from my live rock. It's like a white hovercraft with a blowhole in the center. <its a keyhole limpet (Mollusk... "snail" so to speak)> I was thinking some kind of worm maybe, but really don't have a clue. <false on the former, true on the latter <G>> It is not very flat. Read through Reef Invertebrates, but nothing looked similar. <look again my friend... page 202, the pic labeled Acmaea. Then look to the text for info on Limpets> It's about 3/4" long. Any guesses? <limpets are relatively harmless although not entirely reef safe (may eat coralline algae... other desirable benthic growths... sometimes coral tissue> Thanks, and thinks for all the terrific help you guys provide. Jim P. <with kind regards, Anthony>