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Harlequin Shrimp and <their eating> mini Brittle Stars
Re: Harlequin Shrimp and mini Brittle Stars, not-so eating 3/12/13
<Mighty fine Mike>
Firstly, thank you so much for the quick reply. It's been just over a week since I introduced the Harlequin Shrimp into my seahorse system for the purpose of controlling my mini-brittle-star infestation and I wanted to follow up my original query. I've fed the shrimp nothing, but have caught him standing on, and presumably eating, a few Asterinas which happened to hitchhike their way into the tank over the years. I've tried to catch him in the act of eating a brittle star to document positively that the Fenner/Gasta camp has it right and Hymenocera elegans will make meals of non-asteroid sea stars.
<Mmm, have just watched your .mov file and see the shrimp jumping out of the way rather than eating... but, you state it's been there for a week... Must be eating something>
Unfortunately, despite risking involuntary commitment by spending countless hours in the dark kneeling by the aquarium with a red LED headlamp like a severely traumatized Navy SEAL ... I haven't yet witnessed anything conclusive. Luckily (for me, not so much for the mini-brittle), an adventurous Ophiuroid happened to be wandering across the glass of another aquarium in the house and in doing so, nobly volunteered itself for research. I plucked the star with a pair of tweezers and placed him near the Harley in the seahorse tank. I've attached a video to this email illustrating what happened next, but for the sake of those without proper plug-ins, slow connections, or quick attention spans... ~spoiler alert~...
not only did the shrimp seem utterly uninterested in the star, at the 25 second mark of the video, the star makes contact with the shrimp and Harley reacts as if he's either annoyed by or frightened of the mini-brittle and jumps away from our intrepid echinoderm hero (who was airlifted safely back to his previous residence). Apologies, also, for the quality of my directorial debut.
<Bet even Spielberg had a few clunkers early on>
Aquarium lighting, back corners encrusted with coralline algae, and a late-model cell phone camera do not a blockbuster make. I doubt I could shop this to any major studio now that the "found-footage" genre is getting tiresome.
Can anyone please tell me what to make of this? I didn't do a head (arm?)
count before introducing the shrimp, but there doesn't seem to be any dent made in the Asterina or mini-brittle populations since the shrimp was introduced.
<Mmm, does take time. Invertebrates have much lower metabolisms than tetrapods>
If he's eating anything, it could only be the locals which are not nearly as substantial as the meaty-looking Chocolate Chip (Protoreaster nodosus) Starfish which I've often seen (in various states of disassembly) alongside Harleys when they're offered for sale. It seems unlikely that the shrimp is too full to manage another bite.
<Patience urged here (Yoda-speak)>
Being a very peaceful tank (the only non-Syngnathid chordate is a very mild-tempered Pseudochromis fridmani) might account for the Harlequin's out-and-about behavior during daylight hours, but after witnessing him pass up such an easy meal, I'm concerned that he's not so much strolling around enjoying the tranquility as much as he's desperately searching for something to eat. Is it time to give him back to the LFS and abandon this biological method of pest control? I won't knowingly let this animal starve.
<I'd wait a few more weeks>
If so, what other methods of brittle star removal are available?
<Best are baiting and trapping... narrow mouth bottle of sorts w/ meaty bait at end>
The stars won't (possibly can't) leave their homes no matter how I try to lure them into the open for manual removal. Commercial traps and bottles are equally ineffective.
The stars smell the bait and wave their arms frantically, but will absolutely not venture out of their safe-zones no matter how close they are to the traps, or how long the traps soak. The rock in the tank is completely fused together with encrusting corals and algae and cannot be removed without breaking down the entire system. Freshwater squirts into infested areas also do not dislodge the stars.
<... maybe moving the tube-mouthed fishes elsewhere... either starving the Ophiuroids or systematically flushing them out, by removing the rock et al. systematically and rinsing, blasting... soda water a fave>
I'm running low on ideas, and you all seem to always have one more up your sleeves.
The last time I was so thoroughly defeated by a small creature without a brain, we just broke up and she kept a few of my t-shirts.
<D'oh! Like an 'ex', perhaps better to just use the/this experience as a vehicle for learning... Maybe a re-read of Alan Watts' "The Book" (another great fave)>
This is way worse.
<And shall pass. Cheers, BobF>
Harlequin shrimp questions... Fdg.
<Mmm, any can... given a look/see...>
Living close to the coast, I decided to try freezing a starfish I collected locally (from a pollution free location to my knowledge) to see if the shrimp would accept it as food. As I have heard of people freezing chocolate chip stars, I decided I would give it a try. Surely enough, the shrimp ate with a small, cut-up piece of starfish within an hour of being put in the tank! This was about 2 weeks ago and I have been feeding him these little bits daily or every other day (taking the older pieces and replacing them with "fresher" pieces) ever since (my tank is 20g with a 20g sump/skimmer/fuge so I don't want to overfeed by any means). I have heard these shrimp do better in pairs so today I ordered one in again and luckily it was female (I could tell by the spots under the abdomen). After hiding for a while, she walked over to the male and acted like she wanted to share the piece of starfish with him. However, he did not want this by any means so I had to give her a piece of her own. She wouldn't stop pestering the male for his piece but reluctantly gave in and is now eating a piece of her own, close to but not right by the male. I'm curious about a few things...
1. Should I feed them one relatively large piece that is big enough to share or should I feed them individual, small (about 2cm) pieces of starfish?
<I'd try the single piece... maybe just slightly larger... every two-three days>
2. Is there anything nutritionally void or bad in general (other than fouling water quality) about feeding these frozen coastal starfish (to your knowledge)?
<Not as far as I'm aware, no>
3. Is it true that they just eat the tubes of the starfish? I often hear about harlequins leaving everything but little calcareous knobs of chocolate chip stars and when I took out (stole...) the first piece of starfish I fed my male, it looked like he began eating the flesh of the star after eating all the tubes. I'm wondering if maybe I should take out the pieces early or not?
<Mostly the tube-feet>
4. How do I know when they are full? Most owners of these beautiful shrimp seem to feed 1 chocolate chip starfish every 2 weeks or so but as my tank is fairly small I don't want to overfeed at all. Will they come out to the front when they are hungry?
<You will learn how to tell, by their behavior... out and about more, looking>
Thank you so much for your help!
<Welcome. Bob Fenner>
Asterina Stars As A Food Source: Setting Up A Breeding Tank
Harlequin Shrimp Feeding 4/1/09
Family Gnathophylliidae, Harlequin Shrimps 3/9/09 Hi all, I should start out by saying I love wetwebmedia.com. I think I have learned more here than from all other online sources combined. <Ahh, Landon... it is comments as yours here that have driven me on, inspired my efforts> After reading the entire page on Harlequin Shrimp, I have a few questions regarding a pair I have had for about a month and a half, but first, some background info. I had my LFS order me two Harlequins and luck would have it they turned out to be a pair. I sexed them using the information from Charles and Linda's page on Harlequin Breeding to verify this. One of my Harlequins lost a defensive claw within the first few days of being placed in the tank, a result of getting it caught on something, or maybe transport damage I assume. This loss has not affected his health otherwise, and although he did not grow another with his recent molt, I am certain that it should grow back in a successive molt. <Agreed> The two reside in a 8 month old 12G Aquapod Nano that has been modded a bit to provide stability for the system. I have a ReefKeeper 2 controlling the tank. I have a fan to cool the water if necessary and replaced the stock pump with a MJ 900 to reduce heat also, so the system stays within .5 deg F of 78. I have put some acrylic in place to make the overflow skim the surface to eliminate the problem of surface scum. Chemical levels are fine, and a refugium with LR rubble and Chaeto has been setup with LED lighting in the back chambers (reverse cycle). I also have a small bag of De*Nitrate for extra bacteria growth space and another even smaller bag of Phosguard to help with the filtering process. I have several colonies of Zoanthids, Palythoas, mushrooms, and one LPS torch coral along with some star mats in the tank. The only fish in the tank is a Ocellaris clown (his buddy became a victim of the pump intake after jumping over the back wall and I believe I will be content with 1 fish, since this tank is more about the shrimp). Other than the Harlequin Pair and the Ocellaris, the only other motile stock are a constantly spawning pair of Cerith snails, and about 6 small blue hermits. Now that all background information is covered, on to a few questions: 1.) How often should I be feeding a mated pair? <Mmm... depends on the type/amount of food... some folks use small Seastars, urchins... that live/last for quite a few days. but once a week, two weeks> Specifically how often so as to keep them well fed, and/or should this be increased to facilitate spawning? <Mmm, again... "they" will let you know by their behavior> Currently I feed them legs off of chocolate starfish I keep in a refugium for my large tank. I feed them 1 leg a week minimum, sometimes two. <Brings to mind a joke about a dog named "Lucky"> They eat the leg in about 3 days, so should I let them wait a few days, or should I immediately replace the eaten leg with another to keep up with their appetite? <I'd wait about four days...> I only feed the legs (usually 2-2.5") and never place a whole chocolate or the central piece in the tank because I do not want it eating my coral. <Good point> 2.) I also have another tank that has been growing Asterina stars like crazy, I pull out about 50 a week and just toss them in a plastic container where they dry out. Can I feed the Harlequins these dried Asterinas? <Don't know if they'd accept these dried... I would feed them live> I don't want to place them in the Aquapod alive, because I fear they might take over like they have virtually done in my other tank. <Not much of a risk I assure you> I thought they might make a good supplement to their diet of chocolate stars, but have wondered if it would be healthy to feed it to them after they dried. <Me too> 3.) The tank is small as only has two pieces of LR in it (see attached photo), and the Harlequin Pair usually hang out behind the two pieces under a slight overhang, or under an overhang on one side. Should I provide them some sort of cave? Or is this partial cover enough? Remember I would not mind facilitating breeding if possible. <Mmm, I do think what you have is enough> 4.) Would it be best to remove the one clown and feed nothing to the tank other than the starfish leg? <I'd likely leave the clown in... for interest, picking bits about> I assume this might help in water quality, and the snails can just eat the algae that grows on the glass, but what about the hermits? Currently I feed the clown a few drops of my thawed Mysis/Brine that I feed to my other tanks. <Sounds fine> 5.) What would be considered the best salinity to have in this tank for shrimp considering their other tankmates/corals? I currently keep the tank at 1.024, or ~33ppm. <I'd raise this to 1.025-1.026... 35 ppt not million> 6.) Is there anything else I should be doing to take of my Harlequins that you can think of? <Mmm, nothing that "jumps out"> I assume the only other major issue would be making sure the iodine levels are perfect, and I have ordered a Salifert test kit to begin testing that. <This (I2) I would only supplement on a punctuated basis... likely timed with water changes> I really want to thank you guys for creating such a unique place to learn about reef keeping and hope that you guys can keep up the good work. Thanks in advance, Landon <Welcome my friend. Thank you for sharing your thoughts and experiences. Bob Fenner>
- Harlequin Shrimp - just found out its nor a sexy shrimp it's a harlequin shrimp. <That explains a lot.> What do I feed them besides Seastars? <Ummm, nothing... they pretty much only eat Seastars - I used to feed mine chocolate chip stars, probably the cheapest you can find rather than the really pretty ones like Linckias and Fromias. Cheers, J -- >
- Feeding Harlequin Shrimp - to feed the harlequin shrimp should I cut a Seastar into pieces when it's alive or should I kill the Seastar first, if so how do I kill it, or should I just put a Seastar in the tank? <Just put the Seastar, whole and alive in the tank. The shrimp will know how to handle it.> how often should I feed the harlequin shrimp? <Depends on the size of the last meal and how quickly it was consumed. I would wait a couple of weeks between Seastars.> Sean <Cheers, J -- >
NMA RI Book and feeding Hymenocera To Anthony Calfo or Bob Fenner <Howdy> I having been reading your book for the past two months. You both did a great job and I wanted to thank you personally. There is something I wanted to ask you about it. I was reading about the shrimps. Most of all the harlequin shrimp. I have wanted them for a long time but don't like that they ate Linckia or CC sea stars. <Hymenocera spp. can be trained to eat other foodstuffs... mainly other live echinoderms> In your book you said they can eat those small stars that people get as hitchhikers. Can they really do that? <Yes... akin to Antoine and I and hamburgers... we prefer the half pound (pre-cooked weight) artery-busters, but will inhale a dozen or two White Castles in their absence> If they can would you explain to me how to get enough of them to feed the harlequin shrimp? <Ahh, there's the rub... either grow them (hard to do) or have access to many hobbyists close by who can/will supply them. In actual practice folks with Gnathophylliid shrimps generally buy less expensive "chocolate chip stars"> Do you know people who have done this or is it real rare? If it is rare for the harlequins to eat those stars do you think it is worth the risk to try? <Mmm, worth the risk, but would be prepared for the long haul investment to provide other fare> Where do you find them and do you have to do anything to get the stars to breed? <Asterina species just "show up" on S. Pacific LR sources... might be able to be cultured with a razor blade (ouch!)> I am sorry for all of the questions. I would really like to have the shrimp. Thank you for the great book again. Josh <Thank you for your kind, encouraging words and message. Bob Fenner>
- Harlequin Shrimp Food - Hi Crew I was reading on a message board about harlequin shrimp and they eat star fish. How big of a star fish do they eat and how often? <I used to feed mine a small [2"] chocolate chip star which would last about two weeks - I'd wait a week and then add another chocolate chip.> Also do they eat all kinds of star fish or just some kinds. <As far as I'm aware - all the Asteroidea.> There are star fish that are real small and you can order for Detritivore Kits can they eat those? <They can, but as you might guess, they don't add up to much. Have seen these small Seastars dissolve when touched by a harlequin shrimp. Would need a population of 1,000's to be a useful food source.> Thank you crew, Karl <Cheers, J -- >
Re: Harlequin shrimp Thank you Mr. Fenner. I think I'm going to get them. Do you or Mr. Calfo know how to cut those hitchhiker stars or where to get them? <Cutting them is pretty easy... a single edged razor blade... through the approximate middle... Procuring initial specimens is a bit harder... ask your LFS re... maybe they have some or if they know others who do... or if you have a local marine club...> I will have other stars ready too in case they don't like the small ones. Can you ask Mr. Calfo if he knows how to do it too? <Will do, but he's out of town for a few days> James PS I am sorry it took me a long time to write back. Hot mail is having a bad lag time. <I see... and if you look at the FAQs, someone has written in to help you... though we didn't retain your email address, they did post theirs. Please see here: http://wetwebmedia.com/clnshrpfaqs.htm in a day or so. Bob Fenner>
- Harlequin Shrimp Live Food Alternatives? - Good morning I am a French aquarist with some success (A ocellaris (1977 !) then, later on, Hippocampus kuda and Lysmata rathbunae). I am gathering info about Hymenocera and read your articles and FAQs about it. Very interesting! <Yes, fascinating animals.> But concerning feeding, either on WWM or elsewhere, it is always said to put LIVING Seastars in the tank. That means that a regular supply have to be put in place. Not easy when seashore is several hundred miles away! <Yes, this is the downside to keeping these animals and the leading reason we often suggest that folks not keep them unless they can provide this food consistently. Generally speaking, a higher cost animal to keep.> A much more easy method would be to have the Seastars frozen and to give regularly SMALL pieces of them to the Hymenocera shrimps. <"Would" be, but I've seen no evidence of this to date... as far as I know these shrimp will eat only live food.> With of course the necessity to draw out what has not been consumed, in order not to foul the tank. 1) Would it be a convenient method of feeding (as it is for other meals given to fishes)? <It would if the shrimp would take the offering, but I don't believe that it will.> 2) If not, for what reason? <Hard to say specifically - very little hard research on these shrimp available to the aquarist. Anecdotally I can tell you that these shrimp have a very strong chemo-sense - a live sea-star dropped into the tank will cause the appearance of the shrimp, even if out of sight and separated by several hundred gallons of water. A frozen sea-star probably would not elicit this response. Additionally, there just isn't much to a sea-star and the chances are good that the freezing process would be quite destructive to the parts the shrimp needs to derive its nutrition.> Best regards Roger PS1 : Apologize for my "approximate" language <No worries.> PS2 : I am not sure that questions have to be sent to this address. <They did. Cheers, J -- >
Harlequin Shrimp 8/19/06 Hi Crew, <Hello Michael> Hope all is well with everyone! <Good with me, do not know about the rest of the crew.> I have a quick and painless question that I just can not find the answer for. How long is the life span of Harlequin Shrimp in captivity assuming it has a suitable habitat? I have had a pair for about 1.5 years and curious how long my friends can be expected to stay with me. Thank you in advance for your help. <My first question is...what are you feeding these guys? These shrimp feed exclusively on Seastars in nature. Some people have had good luck feeding them sea stars of the Asterina spp. These type starfish reproduce rapidly in the home aquarium and should maintain a good food supply. I'm guessing that this is their diet. These shrimp can exist with feedings of sea stars as long as three to four weeks apart. As far as life span, years, again, depending on the environment and food supply. They have been raised in a captive aquaculture project at the Waikiki aquarium. I'm thinking Charles Delbeek (spelling?) had something to do with this. Bob may be familiar with this project. James (Salty Dog)> Michael J. Bukosky Re: Harlequin Shrimp 8/19/06 Thanks for the response James. <You're welcome> I have been feeding mine strictly chocolate chip starfish. They seem not to be to interested in any other type. <OK> The female lays her eggs on her tail but I have never seen fry. Will they release unfertile eggs? <Could> If not are you aware of how to raise the fry. <I'm not, but I'm guessing the fry would possibly feed off starfish in the planktonic stage. Bob may inject something here. <<Mmm, no, yes and no. RMF>. You may want to do a search on this or go to your public or large library and ask for some help in this regard. Bob may also know who conducted the aquaculture experiment on this species at the Waikiki Aquarium, and may put you in contact with him.> I have breed many freshwater fish but these guys I cannot figure out. <Would not be an easy task.> Thank you for all the knowledge that Wet Web has given us hobbyists. You guys and your web site are a valuable resource. <You're very welcome.> Now its time to finish the acclimation on my new 8 inch Stigmatochromis pleurospilus. Lets hope he isn't to aggressive for his tank mates! <Good luck, James (Salty Dog)> Fab tips for feeding Hymenocera Harlequin Shrimp 8/9/05 8.9.05 Mornin' Anthony <cheers, my friend> Many thanks indeed for such a speedy and affirmative response to my query. <Always welcome mate> I was looking just now on your page re. Hymenocera and thought I'd relate this to you. I used to keep these 20 years ago and what I did (contrary to what was then current thinking) was to collect small specimens of our native starfish, Asterias rubens and wash and freeze them. Easy for me as I live by and work on the sea. To feed the shrimps I just snipped off enough for that feed. As soon as I dropped it in this true pair strode round the tank, following the scent trail, then pulled out and at the hydraulics, leaving behind just the spiny skin! By the way, I've looked at loads of forums of late and in truth WWM is the dogs wotsits!! Kind regards Steve. <Fabulous tips for feeding Hymenocera! Thanks kindly for sharing this... we will duly post them on the dailies page and archies for the benefit of all. Anthony> Propagating Asterinas for Harlequins? 8/21/06 Currently, I have two saltwater tanks. One is a 6.6 gallon nano reef in which I have a small (1.5-2 inch each) mated pair of Harlequin Shrimp along with soft corals and a few other reef critters (Neon Goby, 1.5 inch Emerald Crab, 1 inch Porcelain Crab. <Don't think I'd want the Emerald Crab in the same neighborhood as the Porcelain Crab, may become a meal.> My other tank is a 20L dedicated to my 4.5 inch peacock mantis shrimp. The only other resident of that tank at the moment is a 4 inch reddish Chocolate Chip Star. Currently I have been feeding my Harlequins Chocolate Chips. <Mmm, no Lorna Dunes?> (well, I fed them once so far. I've had them 2-3 weeks. Been told to feed them about every 2 weeks.) <Could go up to four weeks if necessary.> In fact, the star in my Mantis tank was to be a feeder, but I decided he was too big and I didn't want him getting out of hand and munching on my corals. I am still determining how appropriate of a permanent tank-mate he is for my mantis shrimp. All build up aside, he is my question: I found can buy Asterinas on eBay. I assume some one is cashing in on a pest-ridden tank, just like you see "tulip anemones" for sale there. How feasible would it be to grow a herd or Asterinas in my mantis tank to feed daily or so to my Harlequins? Most people want to lose all their Asterina, I can't find any info on how to grow them. <They multiply like weeds. No special care needed. Read FAQ's here for more info. http://www.wetwebmedia.com/asterinafaqs.htm> That tank gets pretty high in Nitrates from chunks of meaty food being discarded, hidden, then decomposing. Is that a problem or is a dirty tank the way to grow these guys? <Would do a little more maintenance than you are doing. Asterinas are rather small and are not going to consume large hunks of food in one sitting until you have hundreds of them.> Can you think of any other reason why or why not to try this? <Absolutely not, they will reproduce faster than the Harlequins can eat them. Keep in mind, they don't always go after Asterinas. Try it out, see what happens.> If I do, can you imagine any way to keep a bunch of these guys without them reaching "plague" proportions? <Discard them if they get to plague proportions.> I like to see inside my tank. I am in a position to set up a separate (simple) system to grow these guys. If you can clue to me in to ideal parameters for these guys, I may try that. <Nothing critical here, drop in some decent flake food and you are on your way. Just keep normal parameters up such as salinity, pH, etc.> Thanks, <You're welcome. James (Salty Dog)> Andrew Harlequin Shrimp Update 8/3/07 Hi there, <Hello Syd> I was reading your information page on harlequin shrimp http://www.wetwebmedia.com/clnshrpfaqs.htm I am raising and selling these shrimp ( you refer to me when I did this at Waikiki Aquarium, but I now have my own farm). Your answers to people seemed good to me. I can assure you that the shrimp eat pieces of frozen starfish, and seem to do fine on dried starfish. I use only crown-of-thorns stars, for political and cost reasons. Because they are large, it is not good to stick the whole star in the shrimp tank. It is ok to do that with small stars. Anyway, if you want to use any of the info on my website, feel free to do so. <Interesting, and thank you for sharing. Will post for others to see. James (Salty Dog)> Syd Kraul www.sihawaii.com/sydkraul/harly.html
Harlequin Shrimp Diet 6/9/07 I have a recently acquired pair of Harlequin Shrimp and I was wondering if they could survive on a diet of pincushion sea urchins. <Have seen this done, yes... If your pair of Hymenocera will accept these> These are easily collected in my area and would be cheaper than buying starfish almost weekly. Also, how much of the urchin do they consume. <A good deal over time... likely a whole animal's complement in a week or so> I'm worried that if they just eat the feet and leave the rest of the body, <This is correct> it will foul up the water too quickly. <... depends on your system, maint...> I don't mind buying the starfish but it would be nice if I could just pick an urchin off the seawall every few weeks. Thanks for your time. <Only experiment, experience can/will tell. Bob Fenner>
Hymenocera Dining on Ophiuroids and Diadema? 12/27/06 Hello Crew, <Lev> I have an inquiry about Harlequin Shrimps. Do these guys feed on Ophiuroids? Serpent Stars <I have seen this in captivity> and the like seem to be too agile for these little shrimps, but I don't know. Another inquiry, Are they brave enough to tackle a Diadema Urchin? <I would think so, yes> Your article states that they eat urchins, but do they eat any species they get their claws on, or do they pay attention to their tough armor? <Eat their tube feet... piercing them...> Thanks Very Much in Advance, Lev. <If hungry, these Gnathophylliids will consume most any echinoderm they can find, though in most cases will choose Asteroids as their food item of choice. Bob Fenner>
Solo Harlequin -05/11/08 Hi Crew I purchased a solo Harlequin shrimp and put it on my 10 g tank 3 days ago, I threw in a choc chip star and right away it grabs the star and start munching on it... since then the shrimp never let go, for 3 days now its just sitting on top of it (day and night). <This is very typical/normal behavior.> Will it ever let go of it at least once in a while or after it consume the whole thing? How many days before I remove the star from the tank cause I'm worried that it might foul the water since it's very small system? <The "cruel" thing about these shrimp is that, even while feeding, they have an interest in keeping the star alive as long as possible (I believe they might even feed the star). So it might be quite some time before the starfish actually dies. To know when to remove it, monitor your nutrient levels frequently and regularly. When your nutrients spike (or when the shrimp lets go of the poor creature) that's the time to take the star out.> The shrimp is the only inhabitant in the tank (at least for now ?) and it is a SOLO! I've read somewhere in this site that this type of shrimp will not live long unless they are in pair? <Nah, they're fine by themselves. But do be VERY diligent with top-offs, maintaining salinity at 35ppm. They don't like salinity swings.> pls pls pls advise as this tiny creature fascinates me and my family . If ever, can I purchase another one? and take my chances if they will pair...not even sure how you can tell the male and female? how can you tell? Also, will they fight ? I mean, if it so happen that they're both male or female? <I would not risk adding another to a nano tank. They don't need to be in pairs and if the resident shrimp doesn't like the new addition (or vice versa), they can be quite mean (kill each other even).> How many of this species can you keep in this size of tank? <I wouldn't keep more than two. But again, since you already have one, I wouldn't add another.> Can I also add at least 1 goby? maybe a yellow watchman? <Probably, but please read about them first.> how 'bout a clown fish? <I wouldn't.> or some corals too? <Some small soft corals and/or a hardy LPS coral could work. Please see our pages on nano tanks.> I think I'm asking too much for such a small tank! pls enlighten me before I start killing these livestock and my wallet...not to mention my wife. <Nano tanks are tricky, please start here: http://www.wetwebmedia.com/small.htm> 10 g , 2" sand, 2 -10g whisper filter(1st w/ carbon, 2nd w/Chemi pure), 20 lbs LR, heater, 1 Sm Rio (for added circulation) and 15w 50/50 coral life fluorescent. Thanks in advance.... Nemo 1 <De nada, Sara M.> Harlequin Shrimp, fdg. 6/1/08 Hey crew, I am truly intrigued by the species *Hymenocera elegans, *and its their eating habits that fascinate me even more. From the FAQs on your page, and various other sources, it seems they are very specific to consuming live echinoderms such as starfish and urchins. <Yes, usually confined so> My question is that do you know of any successful attempts of feeding the shrimp an alternative source of food. <Yes... have read accounts> While this may sound ridiculous, I was wondering if they have the ability to distinguish from a living and a replica starfish? <Interesting speculation> To me, it seems that in the wild, in it natures way of eliminating excess reproduction of starfish. But to replicate the same in captivity by having to by a starfish for the sole purpose of feeding seems unethical. <One can extend such thoughts to include keeping ornamental aquatics period, or over-populating, polluting the planet with our species to the largest extreme> On the side note, are there pests or perhaps faster reproducing starfish which can be easier to attain, while the shrimp gets its benefits as well? Thanks <I don't "know" well-enough re alternative feeding success to relate others claims directly. All the Gnathophylliid shrimps I've seen kept long-term have been fed live echinoderms. Bob Fenner>