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FAQs on Freshwater Shrimp Identification

Related Articles: Freshwater Crustaceans, Invertebrates for Freshwater Aquariums by Neale Monks, Forget Crawfish Pie, Let's Make a Crawfish Tank! By Gage Harford

Related FAQs: FW Shrimp 1, FW Shrimp 2, & FAQs on: FW Shrimp Behavior, FW Shrimp Compatibility, FW Shrimp Selection, FW Shrimp Systems, FW Shrimp Feeding, FW Shrimp Disease, FW Shrimp Reproduction, & Shrimp by Family, Genus, Species: Atyids: Genera Caridina & Neocaridina (Japanese Marsh, Yamato Numa Ebi, or Amano Shrimp, Bumble/Bee, Crystal), Genus Atyopsis (Bamboo, Wood Shrimps), Genera Attya, Atya, Atyoida (Mountain, Rock Shrimps), Freshwater/Brackish/Marine Palaemonidae Rafinesque, 1815 & FAQs on: Palaemonetes (Ghost/Grass/Glass Shrimp), Macrobrachium (Blue "Lobsters), & FW Crustaceans 1, FW Crustaceans 2, FW Crustaceans 3, FW Crustaceans 4, & & FAQs on: FW Crustacean Identification, FW Crustacean Behavior, FW Crustacean Compatibility, FW Crustacean Selection, FW Crustacean Systems, FW Crustacean Feeding, FW Crustacean Disease, FW Crustacean Reproduction & Terrestrial Hermit Crabs, Hermit ID, Hermit Behavior, Hermit Compatibility, Hermit Selection, Hermit Systems, Hermit Feeding, Hermit Reproduction, Hermit Disease/Health, & Crayfish FAQs, Crayfish 2, Crayfish ID, Crayfish Behavior, Crayfish Compatibility, Crayfish Selection, Crayfish Systems, Crayfish Feeding, Crayfish Disease, Crayfish Reproduction,

FW Shrimp ID         11/11/19
Can you please help me with the identity of these shrimp.? They are freshwater . Thanks
<.... 30 megs... PLEASE read and comply w/ our limit on file size. >
Re:        11/11/19

Thank you!
<DO re-size and resend. Cheers, BobF>
Re:        11/11/19

Ok, I will.
<Cheers; we don't have sufficient webmail space, and when in some other countries, large files are near impossible to download. B>
Shrimp identity        11/11/19

<Dear Wendy, your message appeared to contain no greeting or text, just what seems to be a header ("Shrimp identity"), and the attachments were over 15 MB altogether. We do ask people trim photos down to under 1 MB each, because such large attachments block the server and prevent other emails arriving. We also seem to have lost the text of your message as well, so if you can re-send, ensuring the attachments are kept small, that'd be great. Regards, Neale.>
<<Thank you Neale. This appears to be a grass shrimp species of sort: genus Palaemonetes. BobF>>

Re: New rainbow fish won't eat... Now shrimp ID       9/28/19
Hi again Neale I was wondering if you could ID this shrimp? I have no idea what it is. I thought it was A long arm Murray river shrimp but then after 2 weeks it went a brilliant blue color
<Most likely a Macrobrachium species, possibly Macrobrachium dayanum var. "blue", but hard to say. Cheers, Neale.>

shrimp identification 9/10/11
Hi there
I cannot seem to id this shrimp. I have four of them in my tank which I didn't purchase. I have other dwarf shrimp and I would like to know if this shrimp (pictured) is predatory.
<Are these in a marine or freshwater tank, Lawrence? Cheers, Neale.>

Re: shrimp identification 9/10/11
Hi Neal
This is a freshwater shrimp. These could have hitchhiked from PetSmart. I did buy a plant from there. They sell ghost shrimp, but this doesn't look like the ghosts that they have for sale. I did buy some java and Christmas moss on eBay from overseas, I think it was Malaysia. I thought I only had one, but it turns out I have four of these shrimp. I've been losing some of my dwarf (red crystal, cherry and mandarin) shrimp and thought it could be due to some neon tetras (I noticed the other day after putting some shrimplets in the tank, some of the Neons were trying to nip at them) or these shrimp. I do have some celestial pearl Danios but have not noticed any aggression. After I had sent you the initial email this morning, I checked the label on the liquid fertilizers and noticed there were trace amounts of copper. Which is also another variable over the shrimp loss.

Re: shrimp identification 9/11/11
Hi Neal
Well I also looked at the co2 supplement that I had which is made by API which does contain glutan. I'm sure this would be similar to Seachem excel that we had brushed on before. I was double dosing the tank, so I'm sure that wasn't good for the shrimp. I think I'll stop using the supplements for awhile and see if that makes a difference. One more quick question though. I have several species of dwarf shrimp in the same tank. Will they cross breed by chance?
<Yes, many of the small Caridina and Neocaridina species we keep will hybridise. On the other hand, many shrimps we think are different species are simply colour forms of one single species. The Red Cherry Shrimp is a red form of Neocaridina heteropoda, as is the Blue Shrimp and the Yellow Shrimp, and obviously these will freely interbreed without any hesitation, resulting in greenish coloured wild-type shrimps. It's best to keep single sort of shrimp on their own, if breeding is important to you. >
<Cheers, Neale.>

Shrimp ID 11/27/08
Hiii!!!!!!! I caught 4 wild shrimp at the beach and threw them without hesitation in my 17 gallon saltwater tank. it's been 2 month now they r all the same and tiny except one which is bigger and more colorfull, all the rest are transparent and look healthy. i did everything i could to identify their name or have information about them but NOTHING. 6 days ago i noticed the big shrimp(1 inch) with his belly full of dark green eggs!!!!!!!! everyday the eggs changed and one the sixth day i can notice 2 dots in each eggs,the shrimp look shy and is not eating like the others, what can i do to identify the shrimps, when the eggs r gonna hatch????i really need answers plz!!!! <Heyyyyy! Are you a child, a non native speaker, a person of diminished capacity?..... Please fix your English and re-send. Can you send a picture or two? The color of the eggs is about right. BobF. >
Shrimp ID 11/28/08 i'm sorry for my english and for the spelling, it's not my official language <Ah, no worries. I understand> i just wanted to identify the shrimp i caught, which is pregnant know. <This appears to be a Grass Shrimp, likely the species Palaemonetes paludosus. Bob Fenner>
Unidentified Shrimp... Perhaps a Ghost Shrimp 9/11/07 This is Paul again. <Hola Paul, Mich aqui> I just wanted to send you a picture of one of the shrimp in my tank. I have another just like it. I am currently living in Brazil (Curitiba) and this was a shrimp offered at the aquarium store (www.aquabetta.com.br) I thought you guys might like to look at it. <Always nice.> Maybe you haven't seen one like it before. If you have, can you tell me what its name is? <I could be wrong, but it looks like a pretty glass or ghost shrimp to me. Ghost shrimp are often used as feeders More here: http://images.google.com/imgres?imgurl=http://www.fishlore.com/Pictures/ Profiles/ghost_shrimp_2.jpg&imgrefurl=http://www.fishlore.com/profile- ghostshrimp.htm&h=150&w=250&sz=6&hl=en&start=16& um=1&tbnid=mn4UJo7N5z_kqM:&tbnh=67&tbnw=111&prev=/images% 3Fq%3Dglass%2Bshrimp%26svnum%3D10%26um%3D1%26hl%3Den%26safe%3Doff%26client%3Dsafari%26rls%3Den%26sa%3DG > Thanks a lot. <De nada! Mich>

Re: Unidentified Shrimp... A Ghost Shrimp 9/12/07 Buenos Dias Paul, Mich here again.> I thought ghost shrimp were freshwater. <Can be fresh... can also be salt... I have collected myself from saltwater in the Belmar NJ inlet.> They have been living in my saltwater tank for 7 months now. <Yes, there are several species. Many can tolerate great ranges in salinity. RMF is in agreement with this ID.> Paul

Cherry shrimp with crystal red striping? 2/16/08 Hi guys! You've helped me in the past and was hoping you could help me now. I have a genetic variation that has popped up in my cherry shrimp breeding colony. I have had these shrimp for two years and have no crystal red shrimp. A few weeks ago I noticed a female that I thought had a white stripe due to molting. I got a good look at her last night. This is sure enough what she looks like. I am thinking of giving her her own 5 gallon and a few fellas and see if this mutation pops up more frequently. Any thoughts or comments? Take care, Mary. <Does looks like Neocaridina sp. "Red Crystal" as opposed to Neocaridina denticulata sinensis "Red", but since the latter is an artificial form, it's entirely possible that genetic throwbacks might turn up occasionally. In any case, if you like the shrimp, and are 100% sure that it isn't a specimen of Neocaridina sp. "Red Crystal" that got in somehow, by all means see if you can 'fix' the mutation through further captive breeding. Cheers, Neale.>

Nice. RMF

Mystery Shrimp - Fun with Freshwater Inverts Hey all, <Hey, Chris> I have a rather odd hitchhiker that came with my bumblebee shrimp today. It's about the size of a large ghost shrimp, it's pincer arms are about as long as it's body <This alone screams "Macrobrachium!" Now, Macrobrachium *what* is the question.> and are sort of banded in alternating pale red and grayish-black. LFS said it'd snuck in with the bumblebee shipment and hadn't injured/killed any of the bumblebees in the couple weeks it had been in their tank at the store, but they're not sure what it is. <Fun!> Well, due to various chaos today involving having to return/exchange the tank I got for Xmas (Marineland 10gs apparently have different dimensions than All-Glass 10gs), having to take relatives to the zoo for their annual Zoo Lights event, discovering I either need to buy an adaptor for the power cord and/or change the outlet the tank was going to be plugged into, my new 10g didn't get set up like I'd planned it to be. <Boy, when things go wrong!> So, for the night, the bumblebees (and unknown) all got placed in a 1 gallon tank with an airstone and some algae wafer bits. A short time later, both my sister and myself observed this unknown shrimp would wander the perimeter of the tank trying to pinch the tails of all the bumblebees (who'd jump out of the way). <Oh yes. Macrobrachium shrimps almost all are aggressive meat eaters. Fish, shrimp, anything that holds still long enough to be nabbed, are all at risk.> So the unknown got moved to a separate 1g, where he's mostly watching the bumblebees in the tank next door. <Dreaming of snacking, I'm sure.> (The bumblebees now appear much happier, munching away on the algae wafer and exploring instead of sitting in groups along the walls) <Probably feeling a touch safer, now that they're not potential meals!> So, can anyone ID this critter? <Your photos are quite unclear (no offense, just an observation) and therefore very difficult to tell anything for sure.... is it possible to get him into a position against a solid background? It'd be especially nice to be able to see his first pair of legs, their shape, color, etc. From what you've given me, the best rough guess I can give you is Macrobrachium japonicum.> I'm probably going to try and take him back, unless someone can convince me he'd be better behaved in the 10g with the bumblebees (and future fish inhabitants) rather than how he acted when stuffed into a 1g with them. <I would not expect him to change his ill manners, not at all. But it certainly might be fun to hang on to him in his own tank, see what he grows up to be! I'm sure he'll worm his way into your heart, even with an unbeatable appetite and a bit of a bad disposition.> I'm hazarding a guess it's some kind of Macrobrachium, perhaps? <Almost definitely.> The object it's sitting on in the photos is an airstone if that helps with scale at all. Given the day it's been, you're probably going to tell me I just got a future 5" monster shrimp that eats fish or something ;) <Well.... ;) I do believe you're reading my mind! I'm not at all certain on his ultimate size, though. I'd guess somewhere in the neighborhood of a couple of inches. Small fish would likely be at risk, and small shrimp, as you've observed, certainly aren't safe. But again - don't give up on him just yet! He may prove to be an endearing little dude, well deserving of his own tank. Give him a chance, if you can.> Thanks again for any help you're able to provide, Chris <You betcha.> --Addendum-- A friend located this photo that sort of looks like the unknown shrimp: http://www.shrimpcrabsandcrayfish.co.uk/Shrimp.htm?Longarm.htm~mainFrame (scroll down to Striped-Hand Prawn and click on the image). Although this site's photo is a bit redder than the one I have appears. <This picture looks very much like Macrobrachium japonicum to me.> And it seems to be the only site on the internet that uses the name Striped-Hand Prawn (aren't common names fun to deal with?) <Ugh. I think the world would be a far less confusing place if we simply scrapped ALL common names. *sigh*> Also, I already checked through the photos at http://www.wirbellose.de/arten.html#Großarmgarnelen to try and ID it with no luck (Remembered the site from when it was pointed out to me in the forums by vintage_fish <Hey, that's me! ;) > several weeks ago in regards to a different species) <Try this one: http://www.wirbellose.de/arten.cgi?action=show&artNo=220 . Do please look very closely at the faint striping on the legs (I bet this is a juvenile or young female) and compare with your shrimp. Also, try a Google search on Macrobrachium japonicum and check out some of the pics that come up. If at all possible, try to get a clearer pic on a plain (perhaps black) background. In any case, a fun little fellah to find out more about, if you can spare a tank for him! Wishing you well, -Sabrina>
Mystery Shrimp - Fun with Freshwater Inverts - II Hi Sabrina, thought you might get that e-mail ;) <It strikes me that there simply aren't that many shrimp-obsessed people around.... *sigh*> Thanks for the help, I think you may be right with the species, maybe this one just hasn't gotten its full color yet since it lacks the markings along its sides. I located this site: http://www.aquajapan.com/encyc/shrimp/palaemonidae/macrobrachium/japonicum_e.html <I've seen that one, hoped you'd Google the name and find it - glad you did> That has two pictures of females, the lower one reminds me a little more of what mine is. I'll try to get a better photo sent in (or posted in the forums) soon, still trying to figure out proper fish photography with a digital camera (best results so far have been with tank light off and flash on in that 1g). <"I feel your pain" - my shrimp photos are currently far worse than yours, so don't feel bad, not at all!> The bumblebees are now in the 10g (blending in with the Fluorite), <They are goo at that.> I was going to try reintroducing the bully in the 10g after a few days (and after I add some rockwork for hiding spots) but given this info, I'll just keep him in the 1g while I figure out what to do with him. <A good plan. Surely you've got room for a smallish tank somewhere? He'd probably be fine in the 1g for a while.> LFS has informed me their return policy on livestock only applies to dead livestock. < .... That's simply insane. And stupid. And insane. So, let me see if I've got this right.... They won't take it back and sell it, but if you kill it and bring it in, they'll refund you? That's.... Insane.> Happily, one of the other Aquamaniacs moderators has offered it a home if I don't/can't keep it, since she has two "shrimpzillas" already that she was sold as ghost shrimp (she thinks she's narrowed down the ID of hers to either Indian or Thailand prawns). <Heh, if it weren't that shipping costs suck, I'd gladly offer the li'l guy a home. Do consider keeping him, I think you'd have fun learning about him. The larger, aggressive shrimps can have a lot of personality (or seem to, if you're a shrimp nut like me!).> Thanks again for the help, Chris <Any time. Wishing you and your shrimpums well, -Sabrina>

Shrimp/Crayfish As a Valentine's Day gift for my two sons, my husband purchased two African Clawed Frogs, while the man at the pet store was trying to catch the albino frog, he came across a little guy my oldest son likes to call "Pincher." He gave him to us for free since he wasn't sure what he was. I think he's either a shrimp or crayfish of some kind. How do you tell the difference between the two? He's about 1 inch long with two pinchers and a grayish/brown color and a flat fan like tail. I would greatly appreciate your answer. Thank you. Susan <Hi Susan, generally crayfish are larger than shrimp. It's hard to say without a picture. Does it look like any of these: http://www.thekrib.com/Fish/Shrimp/ Regards, Gage>

Shrimp/Crayfish I am going to try and get a picture sent to you of "Pincher". <Awesome> I looked at the site you sent and couldn't find any one shrimp that looked enough like him, they all resembled him but not enough for me to say he's a shrimp. The only other way I can describe him is he likes to hoard food, he at first didn't mind the African Clawed Frogs but then suddenly started to chase them around and even pinched off some of the little albino frogs toes. <Maybe a crayfish, they are pretty aggressive.> He has dug himself a little home in the gravel under a decoration in the tank. I know this probably doesn't help you much more, so like I said I'm going to try to get a picture sent to you. Thanks for all your help. <In my experience freshwater shrimp will usually do their best to hide and avoid confrontation with anything and everything. This sounds like a crayfish to me, I named mine "fish pinchin' crawdad" I'm working on a country song about him. A picture would be great. Regards, Gage> Susan

Macrobrachium rosenbergii information Robert, Around 14 years ago I purchased three "Blue Lobsters" from a pet store in Mt. Pleasant, MI. Later on I learned that they were known as Macrobrachium rosenbergii. These three invertebrates were the most interesting aquarium pets that I had ever owned. They are long gone now, but I recently purchased a 125 gallon aquarium which I intend to put my larger Cichlids in. Thinking about what to put into the empty 55 gallon, I remembered the "Blue Lobsters" which I loved having in the past. My question is where can I purchase them??? I can not find them anywhere in the West Michigan area. Whenever I ask pet shop employees they look at me like I am crazy!! If you might have any information that might be helpful please e-mail me back. <These crustaceans are still about, though not near as popular as they were years back. This one species is widely and intensively cultured as a food organism (mainly in the Far East). It and a handful of new species of interesting prawns, shrimp and true lobsters can be had from larger retailers and etailers. Please contact the folks on our Links Page here: http://www.wetwebmedia.com/links.htm to start your search, and ask your local fish stores if they'll please look, special order one, more for you. Bob Fenner> Thank you, Andy Shearer

Freshwater shrimp? Dear Crew, We have unfortunately had a small tragedy in our freshwater tank (240L, ph6.5-7, temp 75-77, nitrates 0, hardness 3-4)...in with our neon tetras (11), black widow tetras (6), Otos (5), Rams (3), Corys (6) we had had 5 "red claw shrimp". Now from the pictures on your site and on all of the other freshwater shrimp sites, they look like ghost shrimp, but are a reddish/orange color. We bought them from one of the LFS staff who lives in our area and breeds them in her tank. The biggest of these fellows is about 2 inches long, and the smallest about 1 inch. Until yesterday all was well (how can you tell there's going to be a but) but yesterday evening I noticed small red shrimp on its back, scrabbling a bit. I thought this was strange, so turned him over and moved him into a sheltered corner, he seemed to be struggling, so I wondered whether he was molting and turned off the tank lights to minimize stress and left him to it. This morning at work I have received an e-mail from home telling me that small red shrimp is no more. So now I have 2 questions, first of all, do you have any ideas what species these fellows might be? and secondly, what could have killed small red? his legs and claws looked strangely pale and he seemed sort of bunched up (cramp?) but apart from that we have no clue... Any suggestions would be useful, we want to prevent the same happening to the other 4. Thanks for your time. Nicola <Hey Nicola, sorry to hear about your shrimp. It is hard to get a positive ID without a good picture. The common ghost shrimp will not reach 2in. Take a look at the link below, is it one of these guys? http://www.calacademy.org/research/izg/SFBay2K/ghostshrimp.htm My first concern would be water quality. I would do a good water change, and add a poly filter to absorb metals and many other contaminants. Keep an eye on the other shrimp, if it starts happening to the others we will know that it was not a molting complication and can start troubleshooting from there. Let us know how it goes, Best of Luck, Gage.> Nicola Blay, BSc, MSc International Zoo Veterinary Group

Shades of Uwe Werner! Sabrina, hope you're all recovered... <Yes, much! Thank you. Nothin' a little Gatorade couldn't fix.> pls take a peek at the attached pix. This was the FW shrimp I mentioned at IZOO... about an inch long. <Attractive little beastie.> Any idea as to species? <But for the reddish cast, I would almost think just plain ol' C. japonica; my bigger ones in a brightly lit tank have taken on that nice coppery cast to their backs, quite different from the small guys - but the red and patterning on the sides.... no, I think perhaps this is your fellah: http://www.wirbellose.de/arten.cgi?action=show&artNo=094 ("Redbacked dwarf shrimp") Or perhaps this guy: http://www.wirbellose.de/arten.cgi?action=show&artNo=117 ("Red dwarf") I would lean more toward the first of those two, though. Unfortunately, no species name for either, but hopefully an idea as to what they are. Very nice. -Sabrina> Bob F <Do agree with your analysis. Thank you. Bob F>

Shrimp ID <Hi! Ananda here while our resident shrimp experts are off in the wild blue yonder...> I was hoping you might be able to help me ID this little guy that came into my tank as a hitchhiker and where I could find more info. Thanks. Troy <While I personally don't know what species this is (or even if it's saltwater or freshwater!), I can point you at a shrimp site with bunches and bunches of photos: http://www.wirbellose.de/arten.html ...It's a German-language site, but the shrimp species names are still in Latin. :-) Have fun! --Ananda>

The King of Freshwater Shrimp Someone on my message board was looking for info on these guys. <Would you mind sending along a link to the discussion? I would be very, very interested in participating....> I searched all over the web myself and can't find anything but a single picture. I was wondering if you could help me out a bit here with some info on these really neat looking shrimp. Their common name I guess is Vampire Shrimp and the scientific name is Attya gabonese. <Ahh, Atya gabonensis! Dear me, these are my ALL-TIME FAVORITE shrimp - and that's saying a lot, with my major shrimp addiction!! I have never heard of them being called "vampire shrimp", though. In fact, I do not believe there are *any* widely used common names for this animal. Try a search under the accurate Latin name, this should yield some pics. The only good, solid information available on the web is located at: http://www.wirbellose.de/arten.cgi?action=show&artNo=030 . This is in German, so it may or may not be of much help to you. You can translate the page (somewhat) at Google, using their language tools. Some basic info - they get about 6" long at their largest. Juveniles are orange, females (and possibly sub-dominant males?) are grayish-brownish-bluish, and the big head honcho male will get lustrous black and blue. They are a filter feeder, and are of absolutely no threat to even tiny fish or fry. There are actually perhaps even three or four different animals that fall under this name somewhat loosely.... can be found in eastern South America with some variances from their central-western African cousins. As with all filter-feeding shrimp, these MUST be fed in the aquarium; it is a common misconception that the animals will take what they need from the water - our tanks are simply too pristine for that to happen. Sinking foods which break up into a fine dust, or frozen foods that can be mushed up (I like Ocean Nutrition's Formula One and Two for this) are great. These shrimp are largely nocturnal and very shy. Provide them with a lot of rocky places where they can hide - stressed shrimp are *not* long-lived shrimp. To facilitate seeing them once in a while (again, VERY nocturnal), provide with subdued lighting, or lots of floating plants to block out some of the light. They prefer to have areas of open substrate that are not planted, as well; they are quite clumsy. Lastly, and perhaps most important with these and any other freshwater shrimp - please dose your tank with iodine. I use Kent's marine iodine at a rate of one drop per ten gallons every week (NOT the marine dose!). This really, really, REALLY makes all the difference in the world. Another tidbit - I got mine from Toyin at Rehoboth Aquatics ( http://www.rehobothaquatics.com/ ). They were (still are) in EXCELLENT shape and great health. They had poked holes in the nice, thick bag (double bagged) with their pointy legs and all but a couple tablespoons of water had leaked out, but they still did absolutely fine. He is a wholesaler, and may possibly have a store near you that you can get these from, and if not, he may sell to you directly. Another 'site you should check out: http://www.franksaquarium.com/ - he has several species of not-very-common freshwater shrimp, and has been an invaluable source of info for me, too.> Thank you in advance for any help you can give. <Ahh, no, thank YOU for giving me a chance to discuss my favorite critter! As uncommon as they are in the US, it is WONDERFUL to hear of increasing interest in them.> Regards, Kristen <Wishing you well, -Sabrina>

The King of Freshwater Shrimp - II - 03/01/2004 Thank you soooo much for all the info on these really neat little critters. <You bet. And again, thanks for mailing us. I could talk the ears off of corn regarding these shrimp.> Here's a link to the thread on my message board. http://www.aquatiqterrors.com/forums/index.php?s=248e4199c7eb812b3d38122b7b82f115&act=ST&f=46&t=15336&st=0& <Excellent. I've joined (am "vintage_fish") and hope to chat there!> Thanks again, Kristen. <And thank you for helping to increase interest in these awesome little beasties. Wishing you well, -Sabrina>

More Mystery Shrimp! - 10/04/2005 Hello, <Hi! Sabrina the slightly shrimp-obsessed with you today.... And please let me apologize for the extreme lateness of my reply; on top of having been sick and missed some emails in my box a few days back, you've really given some perplexing pictures! Excellent photos, I must add.> I have seen this question before ("Mystery Shrimp - Fun with Freshwater Inverts") but I would like to ask it once again... is what I have actually a ghost shrimp? <Not what is commonly considered to be a ghost shrimp, but it does look like a Palaemonetes species to me. Perhaps P. antennarius - your shrimp seems to have the same bizarre iridescence that they exhibit. They do develop markings like yours shows as they grow, but yours is more prominently marked than ones I've seen.> or is it a "long-arm" - Macrobrachium... because this guy's arm's aren't longer then his body, but he is a bit big to be a ghost shrimp. He is about 4.5cm (1 3/4"). <Not a Macrobrachium, as far as I can tell, but not a "common" "ghost shrimp".> I have posted photos here: http://www3.telus.net/public/al_s/ShrimpPhotos/ I am wondering what the morphological difference is between the Macrobrachium and the Palaemonetes? <Well.... See, you're asking tough questions now! Just kidding, this is a good one. To be quite honest with you, I do not know the difference in systematics between these two genera. They are both in family Palaemonidae, though Palaemonetes shares the subfamily Palaemoninae with a few other genera, whereas Macrobrachium is not in that (or other) subfamily.> is it just the length/size of the pincer arms or am I missing some other key item? <Macro = big, brachium = arm .... All of the shrimps of genus Macrobrachium do have very prominent "arms". Some more so than others, to be sure, but all are quite big. This can be somewhat less noticeable in females, but even most females have really big arms. Also, all of the Macrobrachiums (Macrobrachia? Uhh, I don't know the pluralization of this word!) that I have met seem to have an impressively large rostrum. Some Palaemonetes do as well though, including P. antennarius, whose rostrum can be quite wicked-looking. Physically, those two pincer arms will tell all. Or most, at least. Yours is not a Macrobrachium, as far as I can tell. Now, that doesn't mean it's not aggressive! P. antennarius, if it were just the size of a dog, would take over the world and wipe out humanity. And you'd hear an evil laugh while they did it. Fortunately, they stay at or under 2", so hopefully we're safe. Or maybe that's just what they want us to think....> Thanks, -Rose <And thank you for showing us these great images; I do hope you enjoy this animal. Wishing you well, -Sabrina> Differences between Palaemonetes and Macrobrachium species shrimps.... 9/21/05 Hey Bob! <Sabrina> I know I should know this, or at least be able to find it, but I don't and I can't. I wonder if you know, or can point me in the right direction. <Will try> What, physiologically, ARE the differences between these two genera? I mean, aside from the (macro) big (brachia)" arms"/pincers, what really makes a Macrobrachium a Macrobrachium? What makes a Palaemonetes a Palaemonetes? Both are of the same family (Palaemonidae), though Macrobrachium is in sub-family Palaemonidae.... But.... What determines this? I've struggled a couple days to try to find *something*.... hobby-related websites and the few books that mention shrimps (including Uwe Werner's Aqualog) just talk about care, and those big honkin' arms.... and I can't seem to find any scientific websites that really explain what makes a Macrobrachium a Macrobrachium, or a Palaemonetes a Palaemonetes. Any thoughts? I wish/hope it could be as simple as counting scales, rays in fins, tooth shapes and pharyngeal bones.... Fish are so easy <. <Don't know... w/o "looking"... likely at SIO... but here is the feedback from Google on Systematics of the Palaemonidae: http://www.google.com/search?sourceid=navclient&ie=UTF-8&rls=GGLD,GGLD:2004-27,GGLD:en&q=systematics+of+the+palaemonidae Looks like there are some useful bits here... and I would try the (not ready for prime time) "Google Scholar" as well... Next time you're in town, let's make a sojourn down to the Scripps Library... am facile at searching "the literature". Bob F> Thanks much.... -Sabrina

Shrimp Discrepancy? - 01/19/2005 Hey, <Hola.> I was just admiring your site and I noticed you mentioned P. kadiakensis, a freshwater shrimp. There you mentioned it as a marine species; <Mm, no, just that this particular individual was living in a marine aquarium.... A few freshwater Palaemonetes shrimps can be pretty easily acclimated to brackish or saltwater environments. After looking at the photos that I have available (including a higher res pic of the one in question), I am not convinced that this is (or, for that fact, is not) P. kadiakensis - the only solid information I can find on its tolerance of salinity suggests 20ppt is okay, but 25ppt is lethal.... I also assume that, like with other Palaemonetes shrimps, this tolerance may differ with different geographical populations of the species.> however, it is true freshwater species, not needing salt or brackish water to breed, as I raise them successfully. <Agreed wholeheartedly. The same can be said for other Palaemonetes which can be acclimated to saltwater, as well (though some species have a much lower survivability in larvae in lower brackish or fresh conditions, and vice verse). But, taking into account the areas that P. kadiakensis can be found in the wild, I am inclined to agree - the species of this animal is, in fact, in question.... Unfortunately, I do not have other clear photographs of "known" P. kadiakensis for comparison.... Sigh. Perhaps you have some that I could take a peek at?> The shrimp on your site (bottom pic) was most likely P. pugio or P. vulgaris. <Alas, I do not have access to any clear photographs of either of these - but from the small pic on the site, I think identification is impossible.... The high-res version we have is very, very clear - if you have any photos of pugio or vulgaris, or kadiakensis for that fact, I would be very eager to see, and perhaps get this fellah correctly named! Or maybe I should take a road trip and find some to see with my own two cute little eyes.> It might even be Macrobrachium or a related Palaemonid species. <Mm, if in saltwater, I find it very, very unlikely that it's a Macrobrachium - perhaps I've got this wrong, but I'm not confidant that there are any saltwater Macrobrachiums, or any species of the genus that can take fully marine conditions?> If you have any questions, email me. <Thanks very much for your comments - if you can get any clear photographs of your kadiakensis, I would very, very much like to have a peek! Wishing you and your shrimp well, -Sabrina>

We were told it was a ghost shrimp I don't have a picture, and I don't have an digital camera, but I will try to describe this shrimp the best way I can. It was a huge shrimp. The pet store told us all ghost shrimp grow that big if allowed to live that long. I think that's bogus. Anyways, this shrimp is 3 or 4 inches long, <Mmm, not what folks generally call a "Ghost Shrimp" then. Please see here: http://www.aquariumfish.net/catalog_pages/misc_critters/shrimp_ghost.htm> has long arms with small pinchers on it and a red nose. It's opaque with black stripes. <Sounds like a (small so far) Macrobrachium... rosenbergii... put this name in your search tools> We also bought a dozen ghost shrimp from this place and it looks like there are much smaller animals of the same species mixed with the common ghost shrimps. They (the 'ghost shrimps' in question) have the same black stripes down the side of it. We tried to ID it at the German language web site you suggested to someone earlier but didn't see it. I'm positive it's aggressive as it tore off almost all of a gold fishes tail within 30 minutes of being in the tank. <Yikes! Do separate this animal, schnell!> We're not sure what to do with it. My wife wants to keep it, but if it's going to terrorize the little fish I'm going to put in the Oscar tank and see how it likes the terrorism. <Oh, these two may learn to coexist> I know you don't have much to go on but just envision a ghost shrimp 4 inches long with similar pinchers and black stripes down each segment of it's body and a red nose... Any help you could give us on this would be very appreciated. Thank you... Jason <Read on my brother. Bob Fenner>

Re: We were told it was a ghost shrimp (Not a ghost of a chance) Thanks for your help. We had also bought crayfish at another store. <Man! Pinch city!> My wife didn't want to leave this huge shrimp in with a bunch of white clouds for fear of them getting eaten so we took them out (after trying to catch him, almost impossible) and put in with a small crayfish (had to do some tank swapping). The huge shrimp (which I now believe to be a Macrobrachium lanchester) tried to eat the crayfish. <Yes... would have eventually> I would have thought the crayfish would fight it off and they would go to their respective corners and stay there. <No... like putting me and a pizza in the same room...> Well, that didn't happen so we had to separate the two. I don't think my wife knows what to do with this huge shrimp but she wants to keep it, if you think it can coexist with the Oscars I'll suggest it to her. <If both are kept well-fed, not too crowded...> But the Oscars are only 3 inches long now albeit very aggressive (the result of feeding mostly live food to them, which included ghost shrimp). Eventually I think they would eat it. What do you think? There are 5 of them. Soon there will only be 2 though (55 gal. tank, <... still too small a system eventually> want them to pair off then going to get rid of the others), maybe it could fend off two? I guess I could always get up late at night, grab the shrimp, steam him and eat him with some cocktail sauce, and then blame it on the Oscars? What do you think? <Mmm, worth a try... Bob Fenner>

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