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FAQs about Crustacean Identification

Related FAQs: Crustacean Identification 1, Crustacean ID 2,   Crustacean ID 3, Crustacean ID 4, & Crustaceans 1, Crustaceans 2, Crustaceans 3, Crustacean Selection, Crustacean Behavior, Crustacean Compatibility, Crustacean Systems, Crustacean Feeding, Crustacean Disease, Crustacean Reproduction, Micro-Crustaceans, Amphipods, Copepods, Mysids, Hermit Crabs, Shrimps, Cleaner Shrimps, Banded Coral Shrimp, Mantis Shrimp, Anemone Eating ShrimpHorseshoe Crabs

Related Articles: CrustaceansMicro-Crustaceans, Amphipods, Copepods, Mysids, Isopods, Shrimps, Coral Banded Shrimp, Cleaner ShrimpP. holthuisi Pix, Mantis "Shrimp", Lobsters, Slipper Lobsters, Hermit Crabs, Squat Lobsters, Crabs, Arthropods, Pycnogonids (Sea Spiders),

Systematics of Crustacea: http://www.dnr.state.sc.us/marine/sertc/Martin%20&%20Davis.pdf

Mystery Crustacean - 11/09/06 Hello WWM Crew, <<Greetings Steve>> I have a question about unknown tank inhabitants I just discovered yesterday (see photo- head and eyes of critter at right end of photo). <<Mmm, very difficult to discern anything from this photo>> I've had my tank established since May 2006.  My set-up includes: 125 AGA 20 lbs. LR 80 lbs. LS 30-gallon sump 10 gallon 'fuge Inhabitants include two Fire Shrimp, two Pistol Shrimp, 5 Scarlet hermit crabs, 3 Tridacnid clams, assorted snails, and 8 small fish.  I watch my tank every day and see everything. <<Indeed...why else have it? <grin> >> I added my second Pistol shrimp about 4 weeks ago, which appeared to be carrying eggs.  Last night, I was amazed to find about 5 or 6 of these multi-segmented crustaceans (if that's what they are) scurrying along the sand bottom and along the back glass.  My 6-lined Wrasse and Striped Fang Blenny appeared to be interested in one, but they quickly became uninterested. <<Hmm...?>> These two little fish are the gluttons of my community tank with overly healthy appetites. <<I'll bet>> The mystery critters are transparent, except for some brownish spots along the top of their bodies.  I believe I counted 8 legs along with a pair of mantis-like front arms. <<Interesting>> It has small, short antenna-like appendages on the head and appendages jutting from the tail segment.  Until last night, I have not seen anything like this in my tank.  The segmented body is what baffles me.  If I had to venture a guess, I would say they might be mantis shrimp, but I'm betting they are not. <<Maybe juveniles re>> So, any ideas? <<Honestly...I'm leaning towards the mantis shrimp possibility>> Good critter or bad? <<May be fine (Mantis or not)...just keep an eye on them for any trouble.  If they do grow/prove problematic I'm guessing your crustaceans to be in peril before your fishes (keep an eye out for rapidly accumulating empty snail shells)>> Assuming they are not mantis shrimp, my guess is they are good guys. <<Maybe>> They appear to be scavenging and interested in algae growing on the rear glass. <<Or copepods...>> Thanks for your help. <<Happy to assist>> "I love this hobby, but hate my electric bill!" <<The price we pay...>> Steve
<<Regards, EricR>>

Unknown lobster ... La pistola     7/22/06 We found a small white lobster (about an inch long) with bright red splotches (dots) in our fairly new marine tank. -- It was carrying gravel  into a burrow under live rock and we assume that it was "free" with the live  rock--- <Heeeee! Yes, a hitchhiker...> A blue dot goby is close by and seems to share the  space. <Yes... this is highly likely a Pistol/Alpheid shrimp. Please see here: http://wetwebmedia.com/pistolshrimps.htm and the FAQs file linked above> Is there any way you could help us identify this little guy  (without a picture)?  If so, is there something special to feed it?? Thanks for your help <Mmm, plenty of pix to be found with the family, genus name "Alpheus" on the Net... foods, feeding in the FAQs. Bob Fenner>

Tiny Shrimp 7/22/06 Hey Crew, <Hi> Was just scouring over your site and reading the articles about skunk banded cleaner shrimp. My tank is just about 8 months old now and I have only had one shrimp for some time now.  The other day the shrimp molted and had left some eggs in the molt. So, I left it for a day until the shrimp had taken them all from the molt and placed them again in her swimmerets. <Good>  Now, tonight as I was watching the tank (Mind you I look every night just to see what I have as far as a nightlife in the tank) <I love doing that.> I noticed that there were thousands of what look like teeny brine shrimp in the tank. (Zooplankton perhaps?) <Yep> Now, I know I have a hearty supply of both amphipods and copepods but they scatter when the light hits them. These little things swarm to the light like moths to a flame. <I have had these before as well, basically just one type of plankton.  Fish love them by the way, my wrasse use to go nuts over these things.>   If they are not shrimp and are zooplankton, where would they have come from all of a sudden? <Normal waxing and waning of populations.  They have always been there, just not in large numbers.> I have not made any new additions to the tank, and the only thing that I have been feeding that is not a frozen or prepared food is some phytoplankton for my feather duster. I know this is freeze dried so I am going to assume the likelihood of some type of egg surviving the process and hatching in the aquarium is slim to none. <But does make a nice food source for small shrimp.> Either way I am happy to see a new life in the tank, but again, even if this is not the case with the shrimp, I was curious if there have been any documented cases of single shrimp fertilizing and rearing young on their own? <The shrimp are hermaphrodites so I guess it is possible, but the offspring as so fragile after birth it is nearly impossible to raise these with very specialized tanks.  These little shrimp are just normal microfauna that comes and goes in tanks.  Interestingly I have also seen these in the wild while night diving.  Get some lights and these things come running, followed closely by giant Manta Rays to eat them.  Quite a sight for sure.> Thanks for your time, John <Anytime> <Chris>

Crustacean Conundrum - 03/22/2006 Hello Wet Web, <Hi Mike.>   I've got another question for ya! I just purchased about 30lbs of live rock from an established aquarium. I transported it under water over to my house in about 7hrs. I put the rock (Fiji, Marshall, Tonga) in my tank and was wondering about a couple of little critters running around. I used a flash light at night to see what nocturnal animals would come out and I saw really really small critters (less than a cm, maybe the size of a pen head) running around all over the place. When I flashed the light on them, they seem to glow a little. Do you have any idea what these are? They seem to run around really fast and there are a ton of them. Could they be copepods? <Could be, most likely seeing a mix of copepods and amphipods.> Could this be mantis shrimp offspring? <I don't believe so.> I also saw a couple of other critters that looked like they might be mantis but I'm not sure. I've looked at a couple photos but can't really tell if it's the same thing in my tank. They look like shrimp, they are about a cm long and they are kind of clear or white. I saw maybe 4 of them in my tank. About how big do they get? <These would be the amphipods. Not much larger than you are seeing.> Will they reproduce in my tank? <Yes.> Is this something to really worry about? <Nope.> Will a Green or Spotted Mandarin Dragonet eat these? <Like you wouldn't believe!> Any help is greatly appreciated. Thanks for all the great info on this website. <Start here   http://www.wetwebmedia.com/pericaridanfaqs.htm and explore the related links/articles for more on microcrustaceans.> Mike <Welcome to crazy critter country! - Josh>

Copepods/amphipods/What are these tiny bugs throughout my saltwater fish tank?  2/18/06 I hope you can help me with this major problem.  My aquarium is about  2 months old and we just noticed that there are tiny white, brown and black   organisms and white worms, also tiny.  They are crawling all over our coral  and live rock.  What should we do about this?? We are new with saltwater  tanks and don't want to lose all that we have invested already. <No worries Jenn.  More than likely a population of copepods/amphipods, etc that make good little snacks for your fish.  Will slowly diminish in time.> Thank You,  <You're welcome.  James (Salty Dog)> Jenn

Pistol or Mantis? and adding fish   12/28/05 Hi Crew!   Hope you all had a great holiday. So since the 6 months from my first e-mail to you, things have gone very well.  Tank is very stable, and my skeptical wife now loves it.  We spend at least an hour every evening after we put our daughter down for the night just watching the tank and talking. <Ahhh!> She has named all the fish and has identified personalities in all of them.  Even the dog gets into the act.  (Dog barks when my smaller ocellaris "surfs" the current from my Sea-swirl from 1 side of the tank to the other, which at night it will do 15-20 times in the last hour before the light goes out!)  She has protested any time I talk about moving rock around.  So my point of all of the above is that the tank is really in a great place and I don't want to do any major overhauls. <Okay> Tank basics:  72 Bow Front, 100lbs LR, 20g refugium with 8" DSB, 40g sump, 3/4 sand in display, 2x175w 10K MH on for 9 hours a day, 2x96W PC 420nm Actinic on for 12 hours a day.  2 Ocellaris Clown (2" and 1 3/4").  Foxface Rabbit (4"), Hippo Tang (2 1/4"), Starry Blenny (4 1/2"), 2 cleaner shrimp (3 1/2" each), 2 peppermint shrimp (1 1/2" - new adds) 2 Mithrax crabs.  Oh and 24 Astrea snails, 4 Mexican turbo, 10 Nassarius. So for the last 4 months I have heard a popping from the tank.  I tried trapping, but I kept catching the Mithrax crabs (damn them).  I hear two types of popping.  1 loud popping that occurs sometimes at full light and definitely under just the PC and dark.  The pops only come in 1s and sometimes in 2s, but I would characterize as loud.  Usually several minutes between pops.   The 2nd type of popping is more of a quiet clicking.  Happens just after light goes out.  Happens in multiples, but not rapid fire, usually 15 to 30 second spacing.    So my question is Pistol shrimp, mantis, or maybe both? <Likely Pistol/s... from the loudness, frequency, absence of dead crustaceans (the Mithraculus would be gone)> What exactly should I be looking for? <Small Alpheid/s... they hide, especially during light hours> I have not seen either of them and I have spent many the hour with a flashlight scanning the tank. Nothing has yet been killed.  I have a healthy population of amphipods that could be feeding one or both.  If they were small to begin with would they have gotten much bigger in 6 months? <Likely so... most only get to less than an inch and a half total length> I have herd stories of people having mantis shrimp in a reef and it never killing fish.  Nothing has died should I just wait and see? <I would, yes> Could I have lucked out?  I have a healthy population of coral too.   My rock is secured to a frame so I have good circulation in front and back (at your suggestion).  So, the only thought I have is to slowly pull out rocks 1 by 1 and rotate them into the fuge until I hear the popping coming from the fuge. My concern is that I will stress the heck out of the fish pulling a new rock out every night and of course anything with coral attached will take a potential hit. <You are wise to consider this "cost" here... the "alternative hypothesis"... and to choose the null... to do nothing> My final question is w/ respect to adding fish given this situation.  \I am only planning on adding a few more. 1 Flame Angel (of course my coral and clam may hate me), 1 mandarin goby when the time is right, and a couple of open water swimmers: fairy wrasse or 2, a Chromis or 2, etc... Thanks as always, you all are the best. Oh and Tom from the Fish Doctors in Michigan sends his best (I got lucky and now have a great LFS). <Ahh! Please do mention back to Tom that I say hello as well! Bob Fenner>

Possible Isopod Sighting 09/08/05 Hi, <<Hello Rebecca - Ted here>> Mike G gave me some wonderful advice re my cow fish. He is now gone and the tank is doing much better, <<Great. Glad Mike was helpful>> however, I spotted something really unusual when I was watching a hermit crab catch a bit of flake food this morning. We have a 50 gallon tank with living rock....on the rock, an insect looking being about two millimetres in length and looking just like a woodlouse, with perhaps feelers at one end, was rapidly searching for food. What on earth is it?! Is it a parasite or harmful to anything in the tank?<<It sounds like an isopod. Some are bad news but others are harmless scavengers. Your LR is likely to have lots of interesting creatures inhabiting it. Please refer to these links: http://www.wetwebmedia.com/isopoda.htm http://www.wetwebmedia.com/ca/volume_2/cav2i1/Pods/pods.htm http://www.wetwebmedia.com/pods.htm http://www.wetwebmedia.com/copepodfaqs.htm http://www.wetwebmedia.com/pericaridanfaqs.htm http://www.wetwebmedia.com/amphipodfaqs.htm http://www.wetwebmedia.com/mysidfaqs.htm>> For info, we also have 2 blue cheek gobies 1 yellow tang 1 cleaner wrasse 1 royal Gramma And we are adding 2 yellow tail damsels today. <<The damsels are pretty but may disturb the peace. See this link http://www.wetwebmedia.com/chrysiptera.htm and also search for Chrysiptera. Also, don't forget to quarantine all new fish!!>> Many thanks Rebecca <<You're welcome and good luck - Ted>>

Not Mantis…Amphipod - 06/19/05 I have read on your site that mantis shrimp are a menace to aquarium keepers. <<Hmm...maybe, depending on specie, size...but fascinating creatures in their own right.>> In my saltwater tank's refugium, I noticed several small "things" scooting around and chasing each other. <<Yes...the benefit of a refugium.>> The were moving too fast, and I could not get close enough to get a good look at them.  Today, however, I saw one of these "things" on the bottom sand substrate of my display tank.  I looked at it and it looked like a tiny shrimp.  It was about a quarter of an inch long with its tail curled under.  It was a very pale gray, almost white and they have two antennae on their head.  I was looking online at pictures of mantis shrimp, and they were rather large, and brightly colored.  Can my shrimp creatures be baby mantis shrimp or are they some other species. <<Can't say for sure without a picture, but your description sounds very much like amphipods to me.  A beneficial detritivore and aquarium food source.>> I have not added any decorative shrimp to my tank ever, so they must come from my live rock. <<Yes>> When they are uncurled, they kind of look like a centipede, because they are long and have a lot of legs.  Sorry I can't send a picture, but if you have any idea what they might be, and if the are beneficial or harmful, I'd greatly appreciate it! <<I don't think you have anything to worry about but do have a read here: http://www.wetwebmedia.com/amphipodfaqs.htm>> Thanks, Mike <<Regards, Eric R.>>

Shrimp... Mantis? Dear Crew, I have read on your site that mantis shrimp are a menace to aquarium keepers.  In my saltwater tank's refugium, I noticed several small "things" scooting around and chasing each other.  The were moving too fast, and I could not get close enough to get a good look at them.  Today, however, I saw one of these "things" on the bottom sand substrate of my display tank.  I looked at it and it looked like a tiny shrimp.  It was about a quarter of an inch long with its tail curled under.  It was a very pale gray, almost white.  I was looking online at pictures of mantis shrimp, and they were rather large, and brightly colored.  Can my shrimp creatures be baby mantis shrimp or are they some other species.  I have not added any decorative shrimp to my tank ever, so they must come from my live rock.  Sorry I can't send a picture, but if you have any idea what they might be, and if the are beneficial, or harmful, I'd greatly appreciate it! Mike<<p>Gnats in the Aquarium <<Hola>> I have what looks (though I know they aren't) like a swarm of gnats swimming around in a frenzy in two lower corners of my refugium, right above the substrate. I am not worried as to their potential harm, as I just think of it as food for the reef. They are way to small to photograph, and probably number around 100. They just 'buzz' around in a swarm.  Just wondered if you have any clue, or have seen them before. <<Can't be positive without a picture, but based on your description of their behavior and their location, I'm pretty confident to say these are Mysis shrimp.  And as you have already guessed, yes, they are very beneficial as food for the reef.>> As always thank you. <<Regards, Eric R.>>

Identity of small marine bug Hi WetWeb Crew, <Hello to you> I hope I find you all in good fettle? <So far...> A quick question if I may - I got another small(ish) chunk of LR today for my tank, when I got it out of the bag to go in the tank the lil critter in the photo fell off & I would really like to know what it is or at least that he's not dangerous! - it's currently sitting in a Tupperware tub so a speedy ID would be great so I can either add him to the tank or dispose as appropriate. <I'd toss this... though, I can barely make out that it's a crustacean of some sort> I don't think it's one of those nasty Cirolanid Isopod but I'm not sure, the photo is not great (apologies for that!) the critter's body is curled up in the shot with "legs" splayed out as you can see, the body uncurls when he swims about, assuming he swims head first he has 4 tentacles (2 long 2 short) at the head & looks like some sort of shrimp to me. It's length is about 10mm when stretched & swimming. What do you think? <Thumbs down...> Many thanks in advance - big shout from the UK ;o) Chris
<Thank you, Bob Fenner>

Emerald Crab with bugs Hello: <Hi there> I have a Emerald Crab that looks like it has microscopic bugs crawling all over him. They are the size of a pin head.  His outer shell also has turned white but he seems active and is eating.  Some bugs are red and others white.  Is this a bad sign? <Not necessarily... some other species of crustaceans...> All water levels are normal. My calcium tends to run at 360.  I have not added calcium because I am afraid I will overdose the tank. I use Kent Salt and my tank size is 90 gal. with sump. I was told that some salts give a higher calcium reading.  My tank is almost three months old.  I do weekly water changes of l0% and have 100 lbs of cured live rock. <Okay> Thank you for your help. Patty <I would not be (am not) concerned here with either the "bugs" nor your calcium level. Bob Fenner>

12 legged bright green - Mystery Creature I.D. First let me just say that my husband and I enjoy your site and frequent it often when searching for information. Our tank is approximately 4 months old and is thriving wonderfully. On one of our night time inspections with the flash light we saw a creature just like this one in the photograph (see attached) only it was a gray color. We noticed this one, a bright green colored one, during the day time and was able to photograph it for i.d. It is approximately 1/2 inch long, and has what appear to be 12 legs. Any idea what it is? Thanks so much. Sincerely, Marie Cape Coral, FL <Mmm, interesting... some sort of arthropod... crustacean likely... Likely not harmful... Would just keep my eye on it. Bob Fenner> 
What is It??  Anthony's "MicroCrusty" Hi, Bob... just wondering if you have a notion what this microcrusty might be? They are rather common in fishless tanks/refugia... and usually succeed Amphipods. Their size is only slightly smaller than Gammarus, for example. I sent the pic to Rob T in Hawaii, but he was not familiar.  Any ideas? Anthony C. <Don't know either... though looks vaguely familiar.  Let's post on WWM and ask. BobF>  Grazie :) And a bit of a mention... those mantis like aspects in the front are only developed on larger specimens. The smaller individuals tend to get described like "centipedes" commonly (that is to say... they are very symmetrical... elongate with bullnose ends and sparse large legs. Hard to tell heads from tails when small) Anth- <Yeah, the fancy mouthparts reminded me of the Odonata. B>

Follow-up question re: What is It?? Anthony's "MicroCrusty": Munnid - 3/3/08 Crew, <Hi Russ> First, I'd like to thank you for all you do for this hobby. All of you have greatly contributed to my success as an aquarist (through this site, your books, etc.). <Ah, that's music to our ears. On behalf of Bob and the crew past and present, I thank you very much!> My "question" is more of a follow-up to one previously asked. It pertains to the post titled "What is It?? Anthony's "MicroCrusty"" (http://www.wetwebmedia.com/crustidfaqs.htm, about half-way down the page). I would like to know if anyone has made an ID on this critter. <Yes indeed, it's a harmless, beneficial, herbivorous little isopod in the family Munnidae, commonly called a Munnid.> I have searched everywhere I know to, and this post is the only place I can even find it mentioned. I have an abundance of these critters in my tank and refugium. They seem to thrive just about anywhere; on glass, in the sandbed, on LR, and throughout my Chaeto. <Yep, thank goodness they're good guys, huh!> They do not appear to predatory, as I have never noticed them disturbing any of my tank inhabitants (various fish, corals, sponges, crustaceans, etc.). <That's correct. Unlike their Cirolanid cousins, these pose no threat to livestock and in fact serve as tasty fish treats.> I do occasionally see them squabble amongst themselves, or with the copepods and amphipods, <Yes, it seems to be in their nature and it always makes me laugh to see it in action. Have you seen them perform their little "dance" yet? In the photo at that link (taken from underneath the Munnid) you can see two anterior appendages folded up under the body, akin to a Praying Mantis. Occasionally, two munnids will face off, extend those two surprisingly long appendages out towards each other, grasp tips, and do an odd little dance. It lasts for several seconds then they release and go their separate ways. Why they do this, I have no idea, but it is interesting and amusing to see. It's probably the Munnid equivalent of "You're on my property!". By the way, here's a dorsal/top view of one that was in my tank: http://wetwebfotos.com/usermedia/high/0/2470_145.jpg .> ..but I have never witnessed anything serious come of this (death, predation, etc.). <Nope, their squabbling always seems to be brief/not very intense.> Also, my Synchiropus splendidus loves to eat these guys. <I bet he does!> He actually appears to prefer them over copepods or amphipods. This may be due to the fact that they are much larger than the copepods (easily 10-15x), and seem easier to catch than the amphipods. <Heeheeee! Or maybe they just taste better! Seriously though, I agree with your assessment. Of the three main choices (copepods, munnids, amphipods) munnids are right smack dab in the middle, size-wise. They're perfect for little Synchiropus/Mandarin fishes.> They are able to "run" quickly, but only do so in short bursts, and they do not seem to have any swimming ability. <Nope, they are decidedly more adapted to crawling than swimming. The only time I've ever see one even attempt it is when I've accidentally dislodged it while cleaning the glass. Graceful swimmers, they are not!> My only concern is that I am not sure how nutritional they are. I am not too worried about this, because they seem to have the same feeding habits as my other pods. Also, the mandarin has always been quite plump, colorful, and active. <Yep, I wouldn't be concerned. I imagine that nutritionally, they're about on par with copepods and amphipods.> That pretty well sums up my observations on these guys. <Very impressive, indeed! It's always such a pleasure to find someone who appreciates the smaller, but no less fascinating creatures we have in our tanks. :-)> I hope this has been somewhat informative, or at least interesting to read. <Very much so.> I welcome any/all comments you all may have, even if an ID is not possible. Thanks again for all you do. Russ <It was a pleasure, Russ, and thank you for sharing your observations! Take care, -Lynn>

Here tis'

Microcrustaceans eating Xenia? Hello Again, <Hey, Mike G here.> I'm Baaaack! (Said With the "spooky" Voice) Hope the crew is doing okay. Bob, Anthony, Marina, How are you? I'm good minus the disappearing Xenia, and a couple of critters that might be eating them. Since you guys are the experts, I'll let you tell me. <I'll do my best to help you out> Man, I am going for stupid king 2005. Over the past two three weeks, my xenia started to disappear overnight (in the QT). I did some watching, the big ones disappeared, little ones started to grow, and then all gone. <FWIW, It is somewhat common for Xenia corals to "melt" when in unfavorable conditions or after drastic changes in water parameters. From the descriptions you offer, this is what I am led to believe has occurred. Check the below link for more information on Xenia and Xenia "melting" (Note topic "Xenia Health about 3/4 down the page: http://www.wetwebmedia.com/xeniidfaqs3.htm > Have one cluster left, moved into its own isolation tank after shaking off these guys. Pic1 is both of the critters I found. Pic2 and Pic3 are of the bigger one- easily ? inch in length. Is that what is eating the xenias? Bunch of the buggers in the tank! Huge! Then the top guy in Pic1 and Pic4 (Color is false image for better shape ID) are the 3/16 inch guys. Any ID help would be greatly appreciated. <I am happy to inform you that you have absolutely nothing to worry about, at least from the creatures of which you have attached pictures. Pictures two and three are of Amphipods, marine crustaceans of the genus Gammarus. Picture 4 is of a Mysid Shrimp, genus Mysis. Picture 1 is of both a Mysid Shrimp and an Amphipod. Both microcrustaceans are welcome and benign inhabitants of nearly every marine aquarium. Check these two links for more information on Amphipods and Mysid Shrimp: http://www.wetwebmedia.com/amphipodfaqs.htm http://www.wetwebmedia.com/mysidfaqs.htm Wonderful photographs, by the way.> Thanks in Advance as always, Dan <Glad I could be of assistance. Hope your Xenia problem clears up.> P.S. I can't wait until Bob's Book Arrives - Lot's of answers I bet! He He. <<And many more questions. RMF>>

Popping crustaceans, crowded Tuskfish Hi Was hoping you could help me out with a couple of questions. 1) I have been hearing a popping noise coming from my tank. Its a bit different to the clicking noise that I have experienced before. I have managed to get a look at part of it and I thought it may have looked like a shrimp. I am basing that on its little pinchers (not sure of the technical name) at the front. But it was also kind of spider looking. Perhaps there are a few things crawling around. <... likely either an Alpheid or mantis shrimp> Last night I noticed something strange lying in the substrate. It looked like a brown cigarette butt. I thought that this could have been the shrimp shedding? <Could be> When I woke up this morning it had disappeared. So I assume it was eaten.  Does this sound like a pistol or mantis shrimp? <Either, neither...> I was told that a pistol shrimp can "stun" fish with its noises. <Mmm, not its noise... but its powerful claw> I have a harlequin tusk fish in a live rock only tank. Should I try to take this "shrimp" out or is it okay to leave it. I assume if it is a mantis then I should take it out? <Please read re these organisms... Linked here: http://www.wetwebmedia.com/marind5_5.htm> 2) As I mentioned before I have a Harlequin Tusk in a live rock only tank with a skimmer and sump (bio balls). The tank is around 50 gallons and the fish is probably around 6 inches. I would like to add some more fish - like something really small maybe a few Chromis  or something with very small bio load. What would u recommend? Obviously I don't want them to get eaten - although I have heard the harlequin isn't too aggressive despite its fangs ;) <Isn't aggressive, but this is a small, too small world for this species> 3) How much should I be feeding the Harlequin? At the moment he gets about 2/3 of a cube a day. About 1/3 in the morning and 1/3 at night. I mix it up a bit with brine shrimp and some marine frozen food which has vitamins and other stuff that is meant to be good. <Please look up and read re the species on WetWebMedia.com> Thanks for your help.. much appreciated!! Regards Simon <Help yourself. Bob Fenner>

Maybe a mantis? I think I might have a mantis.  I've read your pages on the mantis but still am unsure.  Maybe it's a pistol.  Here's the symptoms:  new, cured live rock and sand, new setup.  JBJ Nanocube (12g) with about 7 small hermits (can never see them all at once, so I'm not sure), and 4-5 Nerites snails, a bumblebee snail, and one peppermint shrimp (just added last week). The tank has been setup about 2 months now and that's all that's in it - taking it very slowly to be sure all is ok.  During the daytime I hear clicking sounds, like glass marbles hitting glass. << More like mantis, less like pistol. >>  Its only once in a while, very sporadic and usually only a couple clicks at a time.  I've also seen something burrowing in the rock, digging, spewing out white, chalky particles.  My rock is very porous with an intricate network of caves and tunnels throughout.  Pretty sure I saw the little guy one night.  I was hoping all along the popping sounds meant pistol shrimp so I was all set to see tentacles and a claw, etc when, to my disappointment, I saw two little eyes at the ends of long tentacles rotating about, looking back at me.  Bummer.  Mantis.  But here's the thing, with all these crabs and snails and even a peppermint shrimp, I've had no deaths.  He's been in there since the tank has been set up.  I have found some shells with holes, but I'm pretty sure I'm not missing any crabs.  The life in my sand is quite robust with little fleas and bugs crawling all over the place.  Could it be he's just feeding on them and I do not have to worry? << Well it depends on what you mean by worry.  I'd say don't worry.  Yes he may eat a few things here and there, but that is to be expected. I'd think in a 12 gal tank you could remove him if you really wanted to. >> I guess I'd like to catch him, just to be sure.  With the tank pretty much empty, I could also just pull out the rock and dip it.  But so far, it seems, no harm, no foul. << Exactly what I was thinking. >>  However, I do plan to add maybe a goby and other critters (non-fish).  So, maybe this is a good time to get rid of him . . . . what do you think?  Is it mantis?  Pistol? << I think you should bring this up on the www.utahreefs.com/forum site.  Get some local input.  Sounds like a mantis to me, but as you said that doesn't seem to be anything to be concerned about.  Also, if you do get rid of him you'll find a buyer there. By the way, I too am in SLC would like to come get some pictures of him if I can. >> Thanks! << Stay in touch. >> Tom <<  Blundell  >> Baby Mantis Woes? Not Likely Hey guys! I have a 29gal mostly invert tank with about 30lbs of LR.  It's been running for about 3 months now with no problems (other than usual cycling).  And I did put the LR right in my tank.  I was expecting some hitchhikers...most of the LR I got came out of a huge reef that a SW pet store broke down due to having to move. About a week ago I noticed a creature digging a burrow in a fish/invert free area of the aquarium. it would occasionally come out and feed on the tiny white pods crawling around.  I was more fascinated than alarmed by this...I thought if it turns out to be a mantis I'll get a tank for it.  But now.. Last night after the lights were off for about 3 hours I took a flashlight to the tank and saw quite a few close to 20) 1/4" - 1/2" creatures scurrying around to hide.  My fire scallops were going nuts spitting these things out I'm assuming the creatures were trying to hide from the light).  I'm not aware of what baby mantis shrimp look like and I've been trying to find info on them.  These guys looked like clearish crickets with that mantis looking front (two mantis looking arms)  They kept their tails curled under them and when in a corner they would spin around head over tail slowly.  Some had darker horizontal stripes down the back and tail.  I've read a lot of your site and I'm aware that you guys usually need a picture to help. though I don't think I could get a clear enough pic of a 1/2" thing zooming to hide at night.  If you have any clue or advice on what they could be I would be very thankful.  One mantis is ok but 20 make me fear for the animals that I put in there! This is what I have in my tank- 4 red sponges (came with LR) 6 feather dusters (several small feather dusters came with LR) 3 BTAS (came on LR) doreensis? purple with green tips 2 fire scallops (VERY food and time consuming. I'd advise against heh) 1 very protective pair of skunk cleaner shrimp 3 peppermint shrimp 1 neon goby 1 scooter blenny 1 Firefish goby 1 sand sifting star flamingo tongue cowry various snails and small hermits Thanks for your time! ~Angela ***Hey Angela, Yes, I really do need a picture. :) When you describe them as having "two mantis looking arms" then I wonder how familiar you are with mantis "shrimp" (Stomatopods.) Stomatopods have a VERY CHARACTERISTIC appearance, and don't look a bit like anything else. They are really not shrimp at all. I'd be willing to bet that what you are seeing are Gammarus shrimp. A common inhabitant in reef tanks, and quite harmless. Even at the size you speak of, young Stomatopods look just like the adults. By the way, sand sifting stars are not a good thing to have in reef tanks. They eat all the good fauna that you WANT in your sand bed. They are predatory - not good. What you should have instead are Nassarius snails. They inhabit the sand bed, and feed on detritus and other organic matter. Regards

Wild crustacean identification: Sand Flea 7/31/04 I see you've identified many marine invertebrates for folks. Can you identify one for me please? Picture at http://woburn.yafro.com/photo/558971 <our pleasure... this is a common Sand Flea (AKA Beach Flea). They are very common along intertidal coastal areas with seaweed and other decaying vegetation upon which they feed> I found them in wet sand on West Dennis Beach (Nantucket Sound side of Cape Cod, Massachusetts).  Bug-shaped, with a non-segmented shell, maybe 1/2" long, greyish-white, no tail (not a horseshoe crab).   <not even/closely related to Horseshoe crabs... although these fleas are Arthropods> Multiple pairs of segmented legs on the bottom. They like to burrow into the sand (as in a cup of water and sand.) No pincers, so they don't look crab-like at all. I can mail you a better-quality picture than on Yafro. Thanks, David Chesler ID to species/genera is often difficult from an image... especially so in this case with the resolution as it is. Do some web searches now with this common name and sort hits/info with regard for the locale you found these. There are quite a few genera of Sand Fleas... some are very different in appearance from each other. Best regards, Anthony>

What are these little bugs in my tank? 7/29/04 Hi. << Hi there. >> I started a 75 gallon saltwater aquarium last November, went through all the evolution headaches and finally got rid of my algae problems.  I still wasn't having any luck with fish due to Ick so I gave up on the fish and decided to just enjoy my inverts and live rock which is thriving. << I think most hobbyists would be better off if they did what you did and started with a rock/invert tank, and added fish way down the road. >> I also added some Caulerpa and my tank seems to have developed its own little self perpetuating ecosystem with minimal maintenance. As a matter of fact it has sprouted all sorts of life forms.  Baby snails, some sort of bug-like creatures who hang out on the glass, tons of feather dusters and some new sort of macroalgae.  The thing I am really fascinated with though are some little creatures that are swimming in the tank.  They are about 1/8 inch long but are growing, they are transparent and look like miniature humpback minnows or tadpoles with big black eyes and whiskers like a catfish. << I'll take a stab at this and say they are Mysis/Mysid shrimp. >> I know its a long shot without pictures but I was wondering if you might have any idea what they are.  They are too small to photograph with my piddly camera.  Any ideas? << If you do get a picture that would help.  Amazing how many little oddities will sprout up in our tanks. >> JJ <<  Blundell  >>

Quick Pod ID Hello Crew! <Howdy> I have tons of these crawling around my live rock and in my CPR hang-on refugium.  I have searched WWM and still am confused to what they are.  After weeks of trying, finally got a good pic of one.  It is around 7mm long. Is it a copepod or amphipod? Thanks Ray PS  Feel free to use this pic on your site if you want, just credit me with the pic. <Will do. This is an amphipod. Bob Fenner>

What's that noise??? (Pistol/Mantis shrimps) Hi, I am 5 weeks into my first (properly set up) saltwater aquarium.  It's 55 gallons, I have 60 lb. of live rock and about 4 inches of live sand.  I have about 15 blue legged hermits now and 20 turbo snails.  I have evicted 2 stone crabs and a strange looking hairy legged hermit (returned to the LFS). At 3 1/2 weeks I added a peppermint shrimp, and a week later, after several daily water testing that came out negative for nitrate and ammonia, I added a diamond goby.  Needless to say, I don't see my two critters much.  The shrimp seems to hide in the rock as far as I can tell, and I see raised areas (maybe burrows) in the sand in which I suspect the goby hangs out.  I don't remember when it started, but it seems like about the time I added the goby I heard popping or clicking noises from the aquarium in the middle of the night.  I flew out of the bed to make sure nothing was trying to escape from the aquarium, and I couldn't see a thing that could be making the noise.  It doesn't sound like it's coming from my powerheads or my skimmer. It almost sounds like it's coming from around the LR.  I searched online and read about pistol shrimp.  Could I have one that hitchhiked on the LR?<yes> There isn't any way it's the peppermint shrimp making the noise, is there?<no> My best guess has been a hitchhiker pistol that is enjoying the new friend (my goby) and suddenly became more active. <Most likely, could be a mantis shrimp as well. Try to observe at night under dim/red light to identify. If you decide you don't want it, many ideas for trapping here: http://www.wetwebmedia.com/marine/inverts/arthropoda/stomapods/mantisshrimp.htm and beyond> Thanks for your help! <Happy shrimp hunting, nothing like sneaking up on a tank in wee hours to observe critters! Don>

Re: What's that noise??? (Alpheids) Hi, I am 5 weeks into my first (properly set up) saltwater aquarium.  It's 55 gallons, I have 60 lb. of live rock and about 4 inches of live sand.  I have about 15 blue legged hermits now and 20 turbo snails.  I have evicted 2 stone crabs and a strange looking hairy legged hermit (returned to the LFS). At 3 1/2 weeks I added a peppermint shrimp, and a week later, after several daily water testing that came out negative for nitrate and ammonia, I added a diamond goby.  Needless to say, I don't see my two critters much.  The shrimp seems to hide in the rock as far as I can tell, and I see raised areas (maybe burrows) in the sand in which I suspect the goby hangs out.  I don't remember when it started, but it seems like about the time I added the goby I heard popping or clicking noises from the aquarium in the middle of the night.  I flew out of the bed to make sure nothing was trying to escape from the aquarium, and I couldn't see a thing that could be making the noise.  It doesn't sound like it's coming from my powerheads or my skimmer. It almost sounds like it's coming from around the LR.  I searched online and read about pistol shrimp.  Could I have one that hitchhiked on the LR? There isn't any way it's the peppermint shrimp making the noise, is there? My best guess has been a hitchhiker pistol that is enjoying the new friend (my goby) and suddenly became more active. Thanks for your help! <Likely what you're hearing is a/some hitchhiking (as on/in your live rock) Alpheid or pistol shrimp. Please see here re: http://www.wetwebmedia.com/marine/inverts/arthropoda/shrimp/shrimp.htm and the FAQs beyond (in blue, at top) re these shrimps. Bob Fenner>

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,

- Mystery Clicks - Hi I have a two foot salt water tank. It is stocked with the following: 1 Clown Fish 1 Coral Banded Shrimp 1 Dottyback 1 Blue Tang Some live rock There has been a clicking noise (on occasion) coming out of my tank for some time now (around 5 months). I am not sure what it is, but I have been told that it could be a Mantis Shrimp - which is supposedly something that can smash the glass of the tank. <I think a bit extreme for most mantis shrimp...> I have read your FAQ and info pages on the Mantis Shrimp and I found it quite informative however I just wanted to ask the following: 1) I cant find this Shrimp so is it possible that any of my other stock can click? I have been told that Clown fish do some clicking. The clicking sounds like a coin tapping against the class. <Probably not the clown fish. What is more likely is that you have an Alpheid, known by several common names - clicking shrimp, snapping shrimp, or pistol shrimp. Many of these come in very small sizes - less than an inch, and keep well out of site. The only way you know they are there is from the clicking at all hours.> 2) I have noticed a worm like creature on a live rock... it looks like a worm and I couldn't really see a head... it was very quick. I was about to stick a net in and try to catch it, but as soon as I touched the glass it went off like a bullet into the live rock. <Hmm... could still be a mantis shrimp... they can move very quickly.> If this is the culprit then it is possible for me to take this bit of rock out. I only managed to see it at 4:00am one night while I had a hangover. I haven't managed to see anything in normal spectator hours :) I don't know if it is possible to set a trap for it? Because my coral banded shrimp is pretty quick - he will go for any bait lying on the ground. <Mantis shrimp can be trapped.> 3) If it is a mantis shrimp - my concern is that it could crack my tank??? <Probably not unless it is huge.> Is that a true concern? <Not for most, and even then only with the smashers.> Another important concern is my fish - but so far no incidents. <As far as your fish go, they are in more jeopardy from spearing mantis shrimp, and these you wouldn't hear clicking. Smashers typically go after snails and small crustaceans. Look for the mysterious loss of snails, crabs, etc.> 4) Also, another thing that happened the other day (off the topic) - My Coral Banded Shrimp (Lenny) shed his shell. he has done this a few times now.. It is quite an impressive process. Anyway it seems as though one of his legs (or arms) is a bit weak or injured. Is it possible that he could have shed prematurely or something went wrong? <Many things can go wrong during shedding, including the loss of life and limb - it's a rather precarious time to be a shrimp. Typically the lost limbs will grow back after successive molts.> He hasn't really been himself. A bit reserved. <Perhaps just tired after the molt.> The Dottyback and blue tang are a new addition and he was going after them a bit. Is it possible that he shed because of these new additions? <Possible, but not so probable. What might be more likely is... well I'll just ask straight out, how much iodine do you put in your tank. Additions of iodine seem to cause shrimp to molt... so if you've been dosing iodine, you might want to cut that amount in half, or better yet test for it before you add.> Your help is much appreciated. Regards Simon <Cheers, J -- >

CRITTER ID <we need more info about behavior, texture, size, feeding habits, etc.. A pic would really be easiest and may be the only way to ID for sure. Best regards, Anthony Please help me ID these critters I've found in my 55 gallon marine setup.  I have about 45 pounds of live Tonga rock.  been going for about 3 months.  a few days ago I noticed these 'guys'.  they range in size from pepper grain to 'rice' length.  They live within the rock and only come out ultra quickly (speed of lightning) and return to their hole.  They seem to be gathering sand grains or pushing out sand grains or eating smaller creatures to small to see.  It happens so fast I can't really tell what they're doing.  However,  I can tell you they all have 2 yellow body sections.  Somewhere around the head is a yellow band and around the mid-body area is another yellow band.   The rest of the body seems to be clear.  I've seen maybe 10 of them.  I'm thinking the actual population in my tank could be multiplied by a hundred or a thousand as far as I know.  It may be impossible to get a picture.  I was shocked when I first noticed one, because I was watching a 'different' creature calmly walking along a rock (possible copepod or amphipod) and this mystery creature shoots out and snatched him up, and returned to his den all in like 1/10th of a second.  But then he must have released him because a second or two later the 'copepod' popped back in the same spot seemingly unharmed and made no attempt to escape.  It was as if this mystery creature was playing around or practicing.   Oh crew of great wetness!! your wisdom is precious! Micah----fellow reefer..man..

Sand "Fleas" Hey Bob, Years ago I would surf fish in Florida with my Family. We always used "sand fleas" for bait. I noticed that they loved to dive into the sand, and did not get all that big. Do you know if they could be used in my live sand substrate to stir it up? Do you know if there are any problems with them? As always, thanks for you response and great advice. Kevin <Likely some sort of Sand or Mole Crab, like here: http://www.assateague.com/mole-cr.html Not easy to keep in captivity, due to life history, being covered, uncovered by tides, waves... but worth investigating for sure. Bob Fenner>

Teeny Tiny Somethins' Hey Bob and Crew! I am so thankful that you super fish guys are out here, I don't know what I'd do otherwise. I have learned so much here, actually, just enough to realize how much I don't know! I do apologize for the length here, I figured it was best if you had more info than not enough. <Yes, we can always sort through what we don't need, but cannot be helpful if we don't have all the information.> I've searched EVERYWHERE, and can not seem to find an answer, alas here I am. I'm sure I'll blush with embarrassment when you give the kindergarten level answer as well, so go easy on me. <I will try.> I am new in the saltwater world, duh, and I am wondering what the little organisms are that are cruising all over the bottom 1/4 of the tank. They are clear and have two little antennas, a head and another section that's a little longer than the head and then a tail like kinda thing. How's that for a vague description? <Good enough, sounds like a amphipod. Type this term into the Google search engine on www.WetWebMedia.com and I am sure it will direct you to more information and a link to pictures.> In a way they kinda remind me of a teeny-tiny brine shrimp. These guys are small, I need to use a photographer's loop to see them. The 55 gallon tank has been up for about 6 weeks, and has cycled. I have 2 penguin 330 bio-wheels, and one HOT Magnum canister filter that does have charcoal in it, (saving for a protein skimmer) a Rio 600 to just create some current, one good size piece of live rock (about 8 lbs.) that has some green bubble algae and some green hairy tufts that the hermit crabs haven't chowed on yet. Oh, and some small clam that was a hitchhiker on it. I have about an inch or two of live sand, and crushed coral sprinkled heavily on top. I am low on $$ from the initial set-up, so I'm forced to take this slow. The only livestock I have are, a Yellow Watchman Goby, and a Green Serpent Star. Which by the way NEVER ate a fish ever, <Yet> and even the Goby likes to hang out with her! So I was mortified when I found out, from reading your info of course, that they are trouble. <Perhaps not. Have you seen a picture of the fish eater?> I was actually going to email you back then toting my Star's humble behavior, when I noticed my damsel was MIA. And since the star looked extra healthy.... well you know the rest. :^( ah, another statistic. <I understand.> Okay, so now that I completely got away from the subject at hand, I'll leave you alone now. I so appreciate any help and info that you can direct my way. Thank you so much for your time, and I'll keep on plowin' through the data! Sincerely, Dee <Have a nice day! -Steven Pro>

Sand Hopper ? (like Dennis?) Hello WWM crew I recently lost all my fish in my 180 gallon tank due to some disease. <hmmm... regular readers of or daily FAQs are probably tired of reading this, but... it surprises me how many aquarists are not told about or do not simply heed advice on having and using a quarantine tank to screen all new fishes... without exception... before they make it into a display. When done, wipeouts are VERY rare. Not picking on you at all my friend... but in a lifetime as an aquarist, I have seen literally dozens of marine fish that were over 10 and 20 years old in various successful aquarists tanks. 26 year old blue Regal tang, 18 year old Marine Comets, 12 year old Sweetlips (!), saw pictures of 32 year old clownfish (!!! and documented). In all cases, strict QT protocol is applied. one of the keys to success with marine aquariums. For the benefit of others reading this post, a 10 gallon aquarium, glass canopy (no light), heater, thermometer and sponge filter are well under $100... perhaps under $50 with sales or used equipment. This amount was lost many times over in a 180 tank of livestock... not to mention their lives. I trust my friend that you weren't advised to put each fish singly through a 4 week QT before entering the main display. Live rock, live sand, love food, plants, etc all the same risk of disease... all need QT> I let the tank sit for about a month with no fish to insure that the disease would go away and now after a month there are thousands of Sand Hopper's everywhere. http://www.imagequest3d.com/pages/current/pictureoftheweek/sandhopper/sandhopper.htm <indeed.. natural plankton that have flourished without fish predators. They are a great blessing! People set up fishless refugiums to keep their tanks supplied with them> Are these Sand Hopper's dangerous to fish or will the fish eat them? Any information you can provide me with would be helpful. <if they have flourished in your system for the last month and you haven't been feeding the empty tank, it is a sign of serious nutrient accumulation. Perhaps the wipeout was related to overfeeding or high DOC levels> Thanks. <keep reading and learning my friend. Do spend time in the Wet Web Media archives to help prevent the wipeout from happening again. Anthony>

Trying to identify a crustacean.  Hello. Every time I go to the Gulf of Mexico, I see these crustaceans which are about an inch and a half in length. I have heard that they are called sand fleas. However, I looked sand flea up and they are definitely not that. These animals are white to light gray or tan (at least in Destin area - I guess because the sand is white), and they burrow in the sand where the waves crash. They seem to go in backwards. They cover themselves completely except for their eyes and I think filter feeding mouth parts. Their carapace is oval (They kind of look like a giant white peanut M&M.) The filter feeding mouth parts (which are two per animal) make an indention in the sand when the water goes back out. Anyway, I really have wanted to know their name for quite some time. I hope this is making sense.  Thank you for your time. Carolyn <I have known them by the same name of "Sand Flea". There are more than few species and genera this applies to. If you'd like the scientific name, we can consult an Audubon field guide or perhaps find a nice online coastal ID website. Kindly, Anthony>

- Is it or Isn't it? - I think there may be a mantis in the new rock because there is a lot of clicking coming from it almost all the time. <Then chances are it's not a mantis shrimp - what is more likely is that you have an Alpheid, a snapping shrimp. Mantis shrimp just don't click that often, compare with some snapping shrimp which click constantly. No worries.> I just put some egg crate over the top. doesn't seem to effect the light amount much of all. <Good deal... now you're prepared for leaping wrasses.> Thanks!!! <Cheers, J -- >

- Is it Or isn't it? It Was! - it was a mantis!! <I should have known better - the live rock from TBS is a well known source of mantis shrimp.> I came home tonight and between a couple of coral polyps was this big reddish brown head protruding from a hole. I immediately removed the rock and put it in a bucket of fresh water. I was taking no chances. I soaked it for 10 min.s and shook the rock and out comes this huge mass of eggs!! <You'll need to cure this rock all over again - you've wiped out everything on it...> then a 2.5" mantis came out very dead. <Makes sense.> I then took the remainder of the rock and soaked it too. If that thing had gotten in my main tank it would have been a disaster. and with those eggs it was like a reef tank version of Alien waiting to happen. all I can say is better half dead live rock than putting that thing in my tank <Uhh... it's not half dead, it's all dead. Cheers, J -- >

Micro-crustaceans? 6/2/04 there are a few hundred of these white curly things that have just started to show up in my tank in the last week. I am sending a few pictures but they are too small to get good detail of what they look like. the best that I can explain them is about the size of the tip of a ball point pen, curly and a lot of them. <I have not seen any pictures yet. But no worries... I am sure that these are harmless plankters if they are plentiful and in plain view (parasites don't appear this way). Likely a nutritious micro-crustacean... copepods perhaps. Anthony>

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