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FAQs about Giant Clam Disease: Social (See also:  Pest Worms of All Kinds, Pest Snails (Pyramidellids...)

FAQs on Giant Clam Disease: Tridacnid Disease 1, Tridacnid Disease 2, Tridacnid Disease 3, Tridacnid Health 4, Tridacnid Health 5, Tridacnid Disease 6, Tridacnid Disease 7, Tridacnid Disease 8, & Pest Snails (Pyramidellids...),
FAQs on Giant Clam Disease by Category: Diagnosis, Environmental, Nutritional, Trauma, Pathogenic, Treatments

Related Articles: Tridacnid Health: Pinched Mantle Syndrome in Giant Clams by Dr. David Basti, Deborah Bouchard & Barry Neigut, Got Tridacna? A beginner's guide to keeping Tridacnid clams by Laurie Smith, Example Chapter from NMA Reef Invertebrates book, on Giant Clams, Tridacnids, A Brief Guide to the Selection and Placement of Tridacnid Clams by Barry Neigut, Bivalves, Mollusks, Lighting Marine Invertebrates

Related FAQs: Tridacnid Identification, Tridacnid Behavior, Tridacnid Selection, Tridacnid Compatibility, Tridacnid Systems, Tridacnid Lighting, Tridacnid Placement, Tridacnid Feeding, Tridacnid Reproduction, Tridacnids 1, Tridacnids 2, Tridacnids 3, Tridacnids 4, Tridacnid Clam BusinessBivalves, Bivalves 2, Lighting Marine Invertebrates,

The possible list of what may be bothering your Clam/s is considerably long. All sorts of fishes, many invertebrate groups have members that will munch of Tridacnids

Tridacnid Maxima Disease 02/09/09 *Sorry, forgot to attach images in previous email* Hello WWM, I have searched all of the five pages on Tridacnid disease and have not found an answer to my question, so I hope that someone will be able to help me. My Maxima clam has been fine for months since I have had him (purchased tank Sept 08, Maxima came with it, in tank at least 6 months before that). In the past few weeks a brown colored film seems to be growing on the shell. <I see this> I have tracked its progress, and it is spreading. The clams behavior seems fine, mantle looks ok, it fully extends during lighted hours, but this recent development worries me. Please take a look at the two attached pictures and tell me if you can identify it. Thanks in advance. Landon <Need much more resolution here to tell... Could be a simple algal growth... of not much consequence... Perhaps a Hydroid colony... a Bryozoan... IF concerned, IF this growth appears to be deleteriously affecting the Tridacnid, I would take the clam out, and scrub the area (underwater) in a bucket of water outside the system. Bob Fenner>

Derasa Clam, hlth., comp. 9/24/08 Hello, this is my first question but I read your recommendations since a long time ago. Sorry my English is not perfect. <I understand you> My reef setup is running since a year and a half ago. Among many corals and invertebrates I have these two clams since a year ago. A derasa and I think a Crocea, but im not sure about that. The two clams where very good till now. The crocea is still very good but I see the derasa not extending the mantle as before like 10 days ago. I try to move the clam when I notice that the two shells were like disassembled and feels like the top shell was going to fell. <Yikes, no bueno> I leave the clam and not touched anymore. I was very careful and Im sure that I didn't do the damage. She opens a little and the color is good and sometimes close and open a little but Im not sure if she can recover by herself. Is not getting worse at least. I include a photo where you can see the two clams and you can see that the top shell is like a couple millimeters off the natural position. The water parameters are Ammonia 0 Nitrites 0 Nitrate 10 Phosphate 0 Carbonate hardness 8 Calcium 400 Temperature 80 I don't have a chiller and its a 30 gallon tank 196 watts PC and the calms are very high and in the center of the tank Thanks!!!! Fernando <I think this animal is being poisoned by either the Zoanthid below or the Polyp above. I would move either the clam or these stinging-celled colonies. Bob Fenner>

Clam and Bristleworm, comp.    7/13/07 Hello WetWeb, I noticed that my clam was not opening up like it usually does so I checked it out and saw a Bristleworm inside of the clam next to the byssal opening. However, it is in a very tight spot and don't have anything small enough to grab it. What can I do about this? Will my clam survive? <Oh dear, it sounds like your clam might be dead. How long has it been since it opened up? The vast majority of bristle worms are scavengers. They show up when something dies or is dying. Chances are that the bristle worm is not there to kill the clam, but is there because the clam is already dead or dying. Sorry :( Sara M.> Mike
Re: Clam and Bristleworm, comp.    7/13/07
The clam was very healthy prior to me finding the worm. <The bristle worms will almost always know when your clam is dead/dying well before you do. But ok, if you insist on suspecting the worm, there are worms from the family Oenonidae that eat clams. They drill holes into their victims to get inside them. You said the worm was "inside of the clam next to the byssal opening." That makes me think it's a scavenger, not a predator. But, if you do find a hole drilled into the side of the clam, you might actually be dealing with a clam worm. If that's the case, you can try to lure out the worm with some defrosted clam or mussel meat. They're nocturnal, so it would be best to do this in the very early morning before lights on and try to catch it with the help of a flashlight. Good luck, Sara M.>

Maxima Clam and Shrimp - 4/29/07 Hello Crew! <Hi Brandon!> I work at a small LFS and we just got a few clams in. One of them (a gold teardrop maxima) is about three inches long and has a shrimp living inside of it. The shrimp is a white-gray color with small black polka dots all over it. It's about 1/2" long and it's pinchers seem to be large in proportion to its body. Not large like a coral banded shrimp but long and skinny and are held out straight in front of the head. The shrimp is hanging out inside the clam around the gills. I wouldn't be too concerned about it except for the fact that the clam is gaping a bit and seems uncomfortable with the situation. Any ideas what kind of shrimp it may be (I can try to get a picture of it but it should be difficult), and how in the world could I get it out if it is possible to? <Hmmm, I've heard of these shrimp, but unfortunately, I'm not sure which species it is. It also seems unsure whether these are parasitic or actually commensal. Please see this link for more information: http://www.wetwebmedia.com/tridacnidfaq3.htm . Also, I know it would be a challenge to photograph, but if you're able to get a good shot of this little guy, please let us know!> Thank you for your help, Brandon <You're very welcome! --Lynn> <<Is a commensal... no worries. RMF>>

Tridacnid, Squamosa...Sorry We're Closed  2/1/07 Hi Guys - <Hi Jim, Mich with you today.> I am a new hobbyist that inherited a 50 gal tank. <Welcome to our salty world.> After eight months with no losses, last month I lost a small green clam (3 inches). I started noticing it with the Tang nipping at the mantle. After a few more days the clam was sick and it died a few more days later. <Sorry for your loss.  Is this tang still in you system?>   A week ago, a larger clam (5 inches) with a brown mantle took to not opening for most of the day (not gaping). I inspected for Pyrams. None. I did find a couple of small starfish outside, which I removed.   <Probably not the problem.> For the last two days, the clam has opened wide in the morning, but when something closes it (today it was an urchin crawling up onto it). It doesn't reopen for most of the rest of the day. For the last few days, I have moved it to inspect it. Afterward it will open and close hard a few times, like it's trying to expel something. Then it stays hard shut. I sure hope its not dying. When its open, it looks normal. <Gaping would be a bigger concern, though it doesn't sound happy.  Sounds like something is irritating it.  Clams will close when something bothers them.  Perhaps the tang is nipping at it?  How is your water temp.  Sometimes clams will close if the temp is out of sorts.>   I ran tests on the water. All seems ok. Water changes are small (5%) and frequent (weekly). I did notice that this all started after I started using Joe's Juice to fight an Aiptasia infestation. I don't use much, but it does burn the coralline. <This could be the source of irritation.  Are you still using it?> Any suggestions? <Mmm, stop using the Joe's Juice and perhaps leave the clam be for a while.  You may want to do a larger water change maybe 10-20% and see if you get any improvement.  Keep an eye on that tang.  It does sound like something is irritating this clam.>   Thanks, Jim <You're welcome,  -Mich>
Re: Tridacnid Squamosa...Sorry We're Closed    2/2/07
Thanks for the thoughtful reply. Yesterday, after thoroughly reading your site, I did a fresh water dip. The clam liked it. <Mmm, I'm not so sure.> Right after I put it back in the tank, as it was doing its expulsion routine, a small starfish (one-legger) appeared on the lip of the shell. I removed it. Don't know if the starfish was inside the clam or if I just missed it as I inspected it. <I guess either is a possibility.> Today the clam is open, although the edges of his mantle are curled. <Yeah, not so sure I would have done the freshwater dip.  Can lead to inflammation of the gills, and further stress this already unhappy clam.> We will see. <I do wish you the best here my friend.>   I would gladly stop using the Joe's juice. How do I keep the Aiptasia at bay? <Several possibilities.  I personally have used Peppermint Shrimp (Lysmata wurdemanni) and had success.  I found the key is these shrimp have to get pretty hungry before they will choose to eat the Aiptasia.  So this may or may not work for you, depending on what else is in your tank if it's possible to not feed your system for couple days without causing harm to the other inhabitants.  Kalk paste is another good option.   Please read here: http://www.wetwebmedia.com/marine/inverts/cnidaria/anthozoa/aiptasia/aiptasia.htm http://www.wetwebmedia.com/ca/cav1i3/aiptasia_impressions/aiptaisia_impressions.htm http://www.wetwebmedia.com/marine/inverts/cnidaria/anthozoa/aiptasia/aippepshrpfaqs.htm http://www.wetwebmedia.com/marine/inverts/cnidaria/anthozoa/aiptasia/aipcheminjfaqs.htm They seem to spring up as fast as I kill them. <They can be pesky little buggers!> Maybe there is a breeder way down among the rocks, but I can't find him without deconstructing the tank (and the sponges and other stuff have really grown, so I am reluctant to move everything). I have thought of shrimp or a copperhead, but I have an eel that is way cool.... <Oops never mind the shrimp, try the Kalk paste.>     Thanks again. Jim <Welcome!  -Mich>
Re: Tridacnid Squamosa...Sorry We're Closed   2/3/07
Hi Guys - <Hi there Jim, Mich here again!> Just an update. All yesterday the clam was open wide, and again this AM. <Oh!  Very good news!> Pulled two starfish off the other blue clam this AM. But everyone seems happy today. <I hope this happiness continues!> Thanks for your help and advise. <Welcome!  -Mich>

Anniversary marked by Maxima Clam feast  6/5/06 Bob, Anthony, Crew. <Tirion> It has been a while since my last mail so I hope to find all of you well. <I'm fine, thanks> I just celebrated one full year of reef keeping and it has been amazing.  From taking it slowly and pragmatically most of the time, to the occasional 'oh my gosh I have to have that', which we all experience.  I couldn't have done it without your collective expertise. Thank you. <Welcome> To mark my anniversary in the hobby; I awoke 2 days ago to a stable tank, everyone hungry, a couple of new frags doing very well.....and a missing maxima clam. <!?> Very upsetting.  Found it several inches away under a patch of xenia.  Shell partially open, cleaner than a shucked oyster. <Who dunnit?> I created a divot/shelf for this creature in which it has lived for a almost a year - in my opinion, perhaps arrogantly, compared to LFS and others I have seen, I would say thrived as it was always fully open, double in size and colorations were outstanding.  Just that evening, all seemed well. I believe there are three possibilities; 2" red Mithrax, posse of rogue hermits, some unseen critter. <Could be...> I have gotten rid of most hermits as I find them, as the little blighters are not great scavengers and lazy enough to bother anything at any time - <Agreed> even now that are picking on the leathers.  The Mithrax is actually friendly and is fed with Nori and algae 3 times a week as to not get ravenous, although in my opinion all crabs are hungry 29 hours a day regardless of how well fed. <Again, agreed... Mithraculus are not what they're promoted to be... can/do get largish, predatory> I am pretty sure that I have few to no predatory worms as I did have several at first, picked and drained the rocks several times and have seen no sign for 7 months. What are the possibilities of smaller, unseen predators, as I cannot imagine even the Mithrax prying open the shell - it was 'clean' inside except for a small piece of connector tissue.  That really leads me to a predatory worm like a Caribbean fire worm (which I did have two of) or some smaller rock dweller I have not seen.  The only starfish that I have are micro brittle stars and have never seen one bigger than a penny.  My fish are a clown goby, scooter, maroon clown, fridmani and two Chromis so I do not believe I have a fish predator. Thanks so much and thanks for your input. Bill <Would have to somewhat of a "group effort" to consume this bivalve in such a short while... I would try baiting the area, checking with a flashlight every hour or so... toward and into the evening. Bob Fenner>

Critters on Clam    4/10/06 Hi crew!  I have some critters on my Crocea and was hoping you could help ID them.  The pictures aren't great, but I fixed them up as best as I could.  The thing right in the middle of the picture is white with brown horizontal stripes.  It's more feathery than tentacley (new word?). <Maybe> It retracts into a tiny tube when startled.  There are 5 smaller ones on the clam's sides.  I am afraid this is Aiptasia- I'm going through an Aiptasia phobia right now- and am dying to save my clam if he is in danger.  He has been thriving recently (happier than ever since we've switched from Kent to DTs!).  If it is Aiptasia, is Kalkwasser safe to squirt at it? <I wouldn't... these appear to be some species/type of Featherduster/Sedentariate tubiculous Polychaete worm... not harmful> The little guy at the top left is also a mystery, but I can't get a picture.  He's always "missing" when the clam closes.  All I know about him is that he has the 2 antenna and is dark brown.  When the clam shuts hard, a white string comes from this guy's direction.  I know this is probably absolutely useless for an ID, but thought you might have an idea? Thank you, thank you! Jen <This may be another worm or a tube-dwelling snail. Again, not a problem. Bob Fenner>


Ailing clam  - 04/07/06 Hey guys.<Hello> I came home today to find my beautiful crocea clam with a near-gaping intake and some pretty sad mantle extension-and its response to light was kind of sluggish. I looked around the tank to maybe try and ascertain the problem, and it turns out there was an Aiptasia with its tentacles stinging the clam. This clam has been absolutely wonderful before this-wonderful mantle extension, deep color, good growth, very responsive and no gaping. I killed the Aiptasia and the clam's looking a little better. But, its intake is still a bit too wide open for me. Is there anything I can do to help my clam along in its recovery? I run my salinity near 1.024-.026 and there is very little to no nitrates(0-5 ppm with weekly to biweekly water changes) and no ammonia or nitrite. I haven't seen any of the fish bug the clam, save for the clam reacting to fish shadows above it. Also, assuming it dies (God forbid), how will I know it is dead-I  know dead clam really messes up a tank. Thanks for your help. <Other than keep a very close eye on your readouts and on the clam itself, there isn't much more I can tell you to do other than wait.  You'll be able to tell if it declines further (loss of color so on).  If this was really the problem, then it should have been minor and your clam should recover.  Like I said perfect water quality here will be the deciding factor.  Also do a search on WWM for more general info.  Thanks Jen S.>

Galaxea VS. Tridacnid  1/8/06 Hey! <'¦is for horses. Just kidding, couldn't resist. Hello.> I recently received a Galaxea (Oculinid) as a package deal on a piece of live rock with a clam (T. Maxima, gorgeous). <Oh yes.> They are both attached to the same large piece of rock. They are both currently doing fine. But, I was surprised the first time the Galaxea busted out with its sweepers. Those are long sweeps! <Oh yeah, have seen them personally at 10 to 12 inches. And very potent I might add.> Anyway, they are not touching the clam at this point, but if the coral continues to do well I am concerned that it might touch the clam in the future. Will the clam be affected? <Generally the sweepers are extended at night when the clam is closed so it should not be too much of a problem. However yes if the sweepers do come in contact with the clam (the mantle most likely) this could cause some mantle recession, which yes is very bad for a clam which needs the mantle for photosynthesis. Keep an eye out.> Do these kids need to be sent to different areas of the classroom? <Maybe, just keep a close watch as I mentioned.> Thanks for your help and for fighting the good fight! <Thank you for the encouragement.> Andy <Adam J.>

Tridacnid ligament destruction  11/17/05 Hi guys, <Hello Heidi> I am impressed with your message board, and find myself looking at it frequently; thought I might shoot you a question. <Okay> I am a professional aquarist and care for a Tridacnid display that is on a closed 4500 gallon system connected with a live corals exhibit. I have a 16" derasa, three 10-14" Maximas, and five Squamosas ranging from 5-8". I am writing because something is eating external and internal ligaments on the hinges of all but one maxima, and I don't know who's doing it! My three suspects, upon whom I hope you might comment, are:  1) Pyramidellid snails, 2) another species of snail that looks like Collonista, but tends to collect in nooks around byssal openings and ligaments, so I am suspicious, and  3) bristleworms, whom I have found nestled into a couple of ligaments in early morning hours. <Mmm, could be any or a mix of these. They are most easily observed during night...> Pyramidellids came in on a few aquaculture clams while I was on vacation. Neat. <... best to elevate (in a section of cut off PVC is my fave) such new clams, examine them, brush clean with (someone else's) toothbrush...> I THINK I have them mostly under control via weekly manual removal and scrubbing small enough clams (to free them of egg masses) in a separate floating tub. Numbers of visible specimens are dwindling significantly, but I am concerned that they could be living inside the clams where I cannot see them, and chewing up the ligaments at night. Is this possible? <Mmm, yes...> If so, what can I do about internal snails that I cannot see? I also have 12 six line wrasse to help control the snails. They are very fat, think I need more. <Wait till they evidence themselves, use erstwhile snail predators...> During weekly cleanings, I frequently find a species of snail that looks like ~2mm Collonista nestled into the Tridacnid shell around the ligaments. I would love it if they ARE Collonista and I am just paranoid, but their location in conjunction with the damage makes me very suspicious. I do also find them on the backdrop, far away from clams. I always remove them from the display when I find them, but I am REALLY fighting a losing battle with these guys. They are proliferating like tomorrow is D-Day. Do you know of a species of snail that looks like Collonista but devours Tridacnid ligaments? <Am going to cc the two best people I know of to proffer input here: James Fatherree (finishing a book on Tridacnid husbandry) and Barry Neigut (of ClamsDirect.com)> And lastly, the bristleworms. The exhibit has a live sandbed, with live rock piles that house the clams. Only the big derasa sits directly on the sandbed, everybody else sits on seasoned live rock that has been in the exhibit for ~3-4 years. Only 3 have byssal threads attached to substrate. I have found a fat Bristleworm in the ligament of the big derasa, but that's the only occasion of veritable Bristleworm/ligament association. I look forward to any insights you might have, Heidi Sullivan Animal Husbandry Supervisor Underwater World Guam <Barry, James, please reply back to both of us. Cheers, Bob Fenner> 
James Fatherree's Response Re: Tridacnid ligament destruction  11/17/05
Hi Heidi, That's bad news for sure, but I don't know what would be doing it.  The pyramid snails are blood-suckers, so I feel certain that you could rule them out. You said the other snails look like Collonista, but the only other bad snails that I know of belong to the genus Cymatium or Chicoreus, which look nothing like Collonista (except that they are all snails, of course). I'd suggest plugging these names into Google and find some photos. These snails do get inside the clams and eat them, but I've never heard/read of any that would specifically attack the ligament. Same goes for bristleworms. There are a gazillion different kinds and I'd bet that at least some of them will eat the flesh of Tridacnids, but I can't imagine one attacking just the ligament. I've never heard of such a thing happening. Sorry I can't be more helpful, but this is the first time I've ever heard of anything like what you describe. Really, it would seem quite strange for something to pass up on soft tissue to eat a ligament. Which leaves me thinking it might be some unrecorded disease???? Unlikely, but certainly not impossible.   Take a look at "Hinge Ligament Disease of Juvenile Oysters": http://www.pac.dfo-mpo.gc.ca/sci/shelldis/pages/hldjoy_e.htm  and "Evidence for colonization and destruction of hinge ligaments in cultured juvenile Pacific oysters (Crassostrea gigas) by cytophaga-like bacteria": http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=184265 .  Maybe something similar to these are affecting your clams... PLEASE let me know if you get any answers from anyone else!!! Best of luck, James 

Clam killer on the loose - 1/17/05 Guys (and girls?), <We do have quite a few men and women helping out here....thank goodness!> First off, your web site has to have the most information on saltwater stuff in the whole internet.<Totally agree with this statement and I would like to add that it is a totally free resource paid for by Robert Fenner and our sponsors. Websites are not free but he pays for this out of his own pocket. Also, let's not forget that the people who volunteer pay for it with the time they donate. We should also thank our sponsors. To keep this site free we would not be anywhere without their grand advertising monies. Lastly but not least of all, you the collective readership. Without the questions, retorts, challenges, donations (time and/or money), and suggestions, we would but merely exist on the web! Thanks to everyone.> If there is another site I've not found it. Thank you for your time that you donate! <Maybe you could donate your time too??? We are always looking for a new volunteer or two =)> On to the question. I had a Crocea clam (6") Super Colored from Live Aquaria that lived on the sand and it was beautiful. <Crocea clams are gorgeous but also happen to be the least hardy and most sensitive to many environmental changes, in my opinion.> I had it for about 6 months and then one day I noticed what looked to be a white fleshy chunk laying on the sand behind the clam. <Sounds like the foot was severed off. (Yep, clams have a muscular foot for adhering to rocks and whatnot)> It appeared to have come from the back side of the clam <Underneath actually> and I found that I was able to look through the clam where as I was not able to before. <So sorry to hear about this. I have heard they will develop a new foot but that is usually in ideal conditions. Too many predators to enter through the gaping hole left behind after the foot is missing, though> After another week or so the clam regretfully died (much to the joy of the hermit crabs and snails). <No kidding. Have had this happen twice in four years and the animals seem to rejoice and revel in such sorrow so to speak> At the time I chalked it up to "natural" causes (poor animal husbandry?). <Possible but does seem to happen more often with this species of clam> After about 3 months I got another clam (unknown type, not crocea, about 3") because it came with a rock I wanted. <Hmmmm> This was about 4 weeks ago, it did not live on the sand bed but up on the rocks. <Sounds like it could be a maxima> Anyway, I looked in my tank this afternoon when I went home on lunch and seen another one of those white fleshy chunks on the bottom of my tank beneath where my clam is. <Weird, So something bored through the rock to get at the foot??> To say that I am worried is an understatement. <Understood. I don't even know you or your clam and I am extremely concerned. Not the least of which the Tridacnids are very expensive animal.> I was miserable when my first clam died and I hate for my second or any others to die also. <Understood> My tank is a 75 gal with overflow to 29 gal sump. <Very good. Do you quarantine?>  I have almost pristine water conditions. <Says you. Do you continually test for said pristine conditions? What do you base this on? Just curious, as I know nothing of your water conditions or your skill as a hobbyist. You can pretty much find ideal water conditions on our site if any are in question =) See here: http://www.wetwebmedia.com/ca/cav1i3/Clam_care/Clam_care.htm this was written by our friend Barry Neigut of Clamsdirect.com. I personally buy all my clams from him. A wonderful resource and a super guy to boot.> In my tank I have had the following during both incidents: 1 yellow Tank, <Tang? No problems> 1 3 stripe Damsel, <Nope. He would likely be OK> 1 blue devil Damsel, <Great little fish. Likely not the culprit> 1 coral banded shrimp, <Hmmmm....probably not but might keep an eye> 2 cleaner shrimp, <Nope. Fine> 1 horseshoe crab, <Cool. Love those little bugs> 1 orange sand sifting snail, <No worries> many hermit crabs <Suspect if large enough> and many snails (Trochus, margarita, turbo, Nassarius...) <Absolutely not but there is such a predator in snail form....the Pyramidellid snail> 1 emerald Mithrax crab (with one claw), <Be afraid....be very afraid...I don't trust 'em> many Pulsing Xenia (both Pom-Pom and the silver thinner kind), <Nope not at all> frogspawn, and several other types of corals and polyps. <Not likely culprits but do keep them from stinging the mantle by putting some space  between the LPS and the clam> I hope I didn't forget any important info. <Only you would know ;}> I really don't know what is killing my clams but I really want to find out so I can enjoy having them in my main tank and not have to worry about their safety. <What about a tank aimed at keeping these beauties? Maybe a forty or 50 gallon with a 400 watt metal halide and some live rock in the sump? Add a heater and that would just about do it.....> I am going to move the clam to another tank (27 gal bow front that has been running for 3 months) tonight. <Excellent. This is a great idea provided water parameters are very similar as well as lighting and the lack of predators.> Hopefully it will be safe in there! <I hope so. No guarantees though with clams. Not much else to add but maybe keep an eye on your shrimp and crabs. Water parameters are a must for healthy clams. Let me know what you find out or how it turns out. ~Paul> Thank you all in advance again for all of your hard work and time! Randy

New T. Crocea and Possible Mantis Shrimp(s) 4/9/04  Hi Anthony (or fellow knowledgeable Crew mate):  <howdy!>  I hope all is well with you.  <and with you in kind>  It's been a while but I have something to ask. A couple of weeks ago I placed a beautiful T. Crocea on the bottom of a tank with a sugar-fine sand bed. (I'll skip the tank parameters since they don't relate to the question at hand.) I placed him on a flat rock buried in the sand as I have read one should do.  <yes... excellent>  A few days ago, I noticed that the rock was uncovered around the clam, so I carefully scooped some sand back around the base of the clam to cover the rock again. I thought maybe the flow in the tank had uncovered the rock, or that the clam had blown the sand away at some point. Well, to my horror (okay maybe not horror, but definitely displeasure) I came down this morning to find the clam lying on it side in the sand and the rock even more uncovered. I thought at first that the clam had been trying to move and blown all the sand around, even though he was still attached to the rock by a thin appendage. So, I went into the tank intending to upright him when --- YIKES!! From the rock that the clam was sitting on came three darkish brown figures streaking for the live rock! I took a look at the rock the clam sits on and realized that it wasn't quite as flat as I thought. It has a small groove down the middle that goes directly under the clam. I can't think of anything these might be except mantis shrimp. Are there mantis shrimp that stay quite small or grow very slowly?  <yes, indeed... some with a max size of 1" (2.5.cm)>  These were only about 0.5 - 0.75" long and the rock in this tank is probably at least a year old.  <Ahh, probably just amphipods. Unless you are familiar with them and can rule them out. Do find pics on the net of them (also in our Reef Invertebrates book)>  Also, they swam instead of running along the bottom and moved very quickly. I assume mantis shrimp can swim when they want to do so??  <yes>  Anyway, my new theory is that they dug and tunneled around the clam trying to get to his "soft underbelly." I am going to set a trap near the clam tonight, but I just wanted to check whether this sounded reasonable to you or whether you had other ideas.  <no worries... the trap sounds like a good idea, indeed>  Whatever they are, they don't seem "clam friendly," if you get my drift. They must go!! ...if I can catch them..! That's it for now. Thanks again for all your advice in the past. Take care, Greg  <best of luck. Anthony>

Citron Goby annoying Crocea Clam Hello, <Hi> This has got to be the strangest pair I've ever seen: http://members.lycos.co.uk/precisionpf/aquarium/104_0479.JPG <Good shot!> I just bought this Citron Goby earlier today, and it hid for a while, as is usual for new fish to do in the tank. When it came out a few hours later though, it took a liking to the clam. First it tried to swim into the clam's intake, which the clam didn't enjoy at all. (Thank God it didn't actually make it in) Now the fish just lays on top of the clam's mantle... The clam occasionally sucks its mantle in, and thrusts it back out, throwing the fish off, but he just hops right back on, and a while later, it happens again. Is this normal? Should I do something to try and scare the fish away from the clam? <These gobies will often perch on different subjects in the aquarium whether this be a powerhead, coral, rock, or a clam. While it can at first be disturbing the clam, eventually the clam should get used to such action and not think it's a threat. On a side note, there's really no way to change the goby's mind.> Also, I'm having some problems with persistent red Cyanobacteria. <That bacteria can be a real pain.> I did a 3 gallon water change (12g tank) one day, and a 2g the next, but the stuff just comes back in a seemingly greater amount daily. I've now added Chemi Clean to help clean the stuff out, and it has worked well (I just wanted to avoid using it to not anger any of the life in the tank, regardless that the bottle says it's safe for all invertebrates). I'll be putting in another scoop in two days, and then do a 3 gallon water change to clean out the system. Any ideas what's causing the outbreaks of it? All my system specs are good, negligible nitrates and nitrates, good PH and Alkalinity, no ammonia, etc. Any advice on getting rid of the Cyanobacteria, and keeping it away is appreciated. <Cyanobacteria is often caused by high phosphate levels, low amounts of current (lack of oxygen) and high nutrients. I would first question your flow -- is it strong? Cyanobacteria tends to grow in areas with low flow/low oxygen levels. Cyanobacteria will also grow in aquariums which contain high amounts of phosphate. You say that at after your water changes the Cyanobacteria comes back in greater amounts. This makes me think that your water you're using contains phosphate and/or silicates. I would start testing your water for phosphate as this could very well be the cause of this. If your tank does contain phosphate, I would recommend using a phosphate filter media which will eliminate phosphate - PhosBan and Rowaphos are both excellent (not to mention pricey) products which I would highly recommend for removing any phosphate or silicate in your aquarium.> I also have this problem with green bubble algae that doesn't seem to want to go away either, any ideas on how to get rid of the bubbles without promoting the growth of more of them from popping the bubbles? <For the most part, this is up to you to get rid of. There are a few species of crabs which will consume Valonia (Bubble algae) such as the Emerald Crab (Mithrax sculptus), however, if you feed your tank well most likely it won't. I've also had problems with larger Emerald crabs moving around the rockwork and eating polyps in the genus Palythoa.> Thanks for your help and time. <No problem. Take Care, Graham.>

- What Was that Thing? - Dear WetWebMedia Crew, I was reading through yesterday's daily questions and came across one about a Citron goby hanging out on a clam mantle.  The question included a picture of the fish resting on the clam.  In the bottom right-hand corner of the photo, there are some small red "buds"  growing on a piece of live rock. What is this red organism?  I have the same thing growing in my tanks.  I attached the same picture below. <I think it's a type of algae, but it's kind of hard to be certain as the focus in that part of the image is a little off.> Thank you, Jason
<Cheers, J -- >
Re: Citron Goby annoying Crocea Clam Hello, <Hi again.> Thanks for the info on the Goby & clam. Glad it's not just a strange Goby. <No problem.> A couple more questions: Is it good that a clam extends it's mantle fully? I would assume it is, but a guy a the LFS said that it might be that it's doing that to get more light and needs to be moved. Here's a picture of it with it's mantle fully extended: http://members.lycos.co.uk/precisionpf/aquarium/104_0457.JPG <Yes, it's a good sign that clams extend their mantle fully. Your clam looks quite healthy, too.> And here's the whole aquarium, before a good cleaning: http://members.lycos.co.uk/precisionpf/aquarium/104_0456.JPG (still trying to figure out how to re-arrange the rockwork.) <Looks good.> I use an RO/DI filter and I'm pretty sure that there are no phosphates in it. Lacking a phosphate test kit I can't be sure. Doesn't an RO/DI filter remove phosphates in the water, though? <Yes, however, if your system is old and the filters have not been changes some phosphate may be able to escape into the aquarium. Frozen foods also usually contain phosphate in them.> I'm kind of constrained by space in the tank to put in another powerhead. Maybe some of those mini MaxiJets that are sold will work. <Yes, those will do fine.> Valonia: I'll live with it for a while more. I'm not too fond of crabs, and I've read that it's hit or miss with emeralds. Some will eat the stuff voraciously, while others will completely ignore it. <Correct.> In the full tank picture: Any idea what type of polyps those are? <I see a lot of polyps -- are you referring to the polyps to the right of the clam? If so, those look like Button polyps (In the genus Palythoa).> I got two of them for free at an LFS a few months back, and they proceeded to take over the entire rock. <They can grow quite quick.> Thanks for your help. <Take Care, Graham.>

Re: Citron Goby annoying Crocea Clam And once more. :) <Hi again!> I think the clam looks pretty good. The guy I got it from kept it in the very bottom of a tank, with what appeared to be dim lighting (can't remember the exact wattage and number of gallons). He had had that clam, and another living there for two weeks, and that they had seemed to be hardy. He also told me that the people he's sold them to have had good luck with the clams and that they're rather hardy. Here's a pic of the whole aquarium, showing the current location of the clam: http://members.lycos.co.uk/precisionpf/aquarium/Panoramic.jpg <Looks fine.> I posted tank pics in the 'Nano Reef' section at reef central, and people are saying my clam will no lead a good life if it doesn't die in the tank. What are your thoughts on this? <I will slightly agree with what the members of ReefCentral said - the clam may not do its best under your current lighting. Under only 32 watts of power compacts (I assume are 2x 16wt compacts?), the clam will extremely darken in color. This coloration change is due to increased amounts of Zooxanthellae in the clams mantel which are multiplying to catch as much lighting as possible. While I have seen clams do well under lower amounts of lighting, the majority of Tridacnids (especially those as light loving as the T. crocea) die under low amounts of lighting.> The tank is a 12 gallon with a 32 watt PC fixture installed, and all the tank water parameters are OK. (Sans the Cyanobacteria, which seems to be mostly under control now). <As I said, 32wts isn't going to be best for the clam.> From my talks with the guy at the pet shop, the looks of the clam (it's been in there for 2 or 3 weeks now), and the way it reacts if you even walk by the tank sometimes, it seems to be in good shape. What are your thoughts? <The clam does indeed look healthy, and from the way it sounds, it's also aware that your in its presence -- will the clam continue to act as healthy in another month? In a year? I actually doubt so. Eventually the clam may starve from lack of lighting, which is what I'm worried about.> Once more, thanks for your help. <No Problem.> I'm a bit new to clams, and from what I read and was told, it should be ok the way I have it, but I could always have been misled. <I can't accurately say whether the clam will die or not under your lighting. As I've stated above, I've seen many aquariums successfully house the T. crocea under fluorescent lighting, however, these systems have outstanding water quality and have been setup for an extended period of time. It may live, it may not. It may even take several months to die off, or it may live but grow at a slow rate and show poor coloration. I would personally recommend returning it and refraining from another clam until you have upgraded your lighting. Most of the low light Tridacnid clams (T. gigas, T. squamosa, T. derasa) will outgrow your tank in a short amount of time. The smaller clams (T. maxima and T. crocea) will require more intense amounts of lighting. As previously stated, upgrading your lighting would help quite a bit if you plan on keeping the light-loving Tridacnid clams.> Take care. <You to! Have a good day, Graham Stephan :)> -Enrique

Derasa Clam in trouble 12/4/03 I think there may be a problem with my 4 " derasa. Last week, I found what I have now identified (I think) as either part of or the complete byssal gland lying next to the clam... This clam has been in my care for the last year or so and has never exhibited any sign of a problem. It lies on the substrate and isn't attached to anything. Now the clam is showing signs of stress... Poor mantle expansion, slow to react, gaping. Anybody have any idea what the problem might be? <could be predation (look for tiny Pyram snails like grains of rice) or bristleworms at night (inspect after the lights go out)... possibly a crab although more damage would have been/be likely. Then there is the issue of water quality: light shock from a recent and overdue change in lamps or a large water change/change of carbon that increased water clarity suddenly... clams are also sudden to a large influx of freshwater for evap top-off... or spikes of supplements to the tank that are not adequately diluted> I've heard of larger clams expulsing their byssal gland but never 4 " ones and especially not T. derasa... Thanx Simon <this last assumption is not correct, my friend... there is little discrimination by age/species for the expulsion of byssal matter... rather just a matter of necessity by individual when called for. Still... its not an unhealthy maneuver and signs of stress here indicate a larger problem perhaps. Anthony>
Derasa in trouble II 12/6/03
Anthony, Thanks for taking the time to answer. Unfortunately, the clam died ~24hrs after my e-mail. I  was not a happy camper. <sorry to hear it> The water parameters are all fine and out of all the inhabitants of my 110 gal reef, the clam is the only casualty. <different tolerances too to stressors, and "somebody has to be first" as they say. Point being... don't dismiss the potential for a problem just because everything else currently looks fine. Without knowing your full water chemistry, I cannot concur with the evaluation of water quality> (there's also a 6 inch maxima in there) No Pyramidellid snails or bristle worms either. There IS an elusive crab in there somewhere. <yikes... indeed, no crab is truly reef safe> He's grown quite big since my first sighting.(~1.5 inches of carapace) I know he's in there but I don't see him often. <do bait and trap him. Should be easy enough (crabs are greedy). We have tips for doing this in the WWM archives and in our Reef Invertebrates book> Looks like a type of crab I've heard called "shame face crabs" but I can't be sure. Maybe I should be trying to catch him...? Thanx again. Simon <if it is indeed large clawed like a shame-faced crab, you can be assured it is a threat. Those claws are generally built for eating snails and bivalves/clams. Kindly, Anthony>

Cowries and giant clams Hi, <Howdy> I added a giant clam to my aquarium a week ago.  It seemed to acclimate pretty well, and was generally being left alone by all others in the tank, until today.  This afternoon I found a cowry had latched onto the clams foot. <Foot as at the base? The byssus?> I didn't want to wait around to see if it was just passing by, so I moved it off and relocated the clam to a less vulnerable spot.   The cowry played dead for most of the afternoon, the clam seemed to be ok with the spot I placed it, so no big deal, right?  Now tonight I find the cowry is on the clam again.  This time it's stuck on the clams side.  Does he have the ability to drill through a giant clam shell with his radula?? <Not likely. Cypraeids don't prey on Tridacnids as far as I'm aware>   I have not been able to figure out if he's going to kill my clam or just give up and go away.  Please help. thanks, eve <Very likely the cowry is simply "looking for food" on what it perceives as an "inanimate object". I would not be concerned here. Bob Fenner>

Missing derasa clam! 10/14/03 I added a derasa clam to my 44 gal reef tank a few months ago.  It didn't seem to like the spot I originally placed it in--stayed tightly closed--so I moved it to a corner of the tank, on the bottom where the light wasn't as intense.  It appeared to like that spot, opening about half way, closing in response to shadows, first facing the glass on one side of it's corner, then the next day it would be facing the glass on the other side of its corner.  In other words, active, apparently healthy.   <agreed> I dose the tank with a teaspoon of calcium and 8 drops of iodine daily, per supplement label instructions.  I feed the tank DT's once or twice a week, and use a syringe to shoot some DTs near the clam's intake.   <do go easy on squirting any supplements directly at filter feeders... including such foods> This morning, when I fed the fish in the tank their Mysis shrimp, the clam as usual was open about half way and responded to the shadow of my hand.  About 5pm I passed the tank and stopped to watch a minute.  The clam shell was gaping wide open and the clam was missing!  Where did it go? <clearly was predated by something. A crab in the tank is the most likely candidate. Do trap for one at night with a small glass jar and a satchel of bait (heehee... food clam in a nylon bag or piece of boiled nylon stocking) inside... to see who the culprit is. Happy hunting... sorry about the clam too my friend. Anthony>

Clam Bob, Wanted to share something with you that I was thinking about while I was sleeping. <We've got to stop eating licorice and pepperoni pizzas before dossing down> Had a Black Maxima that I placed in a tank and one of my fish attacked him several times and after the third attach the clam gave up and gapped the size of a quarter. Not knowing what to do, took the clam out and placed him in a quarantine tank with minimal light, no substrate and did some feeding. After 8 days the clam recovered fully. I will just about guarantee that if I had left him in the main tank being so stressed that the critters would have finished him off. So my observation is that if you have a clam in distress and place him in a stress free environment so that he can recover he will most likely do so but leaving him in a stressed situation no chance of recovery. Have done this several times with 98 % success. <Thanks for this... you gapper, gipper> Thought this observation was worth passing on. Not a writer but I think you get my point. :) <Yes... will fwd to the fellow-writing boys. Bob> Regards, Barry, www.clamsdirect.com

Tridacnid Hi, I have a 5" crocea that hasn't opened for a little over a week. I was going to be getting a rose leather, a green bubble and a Galaxea on Friday. My flame angel and my yellow tang, I just noticed, have been picking at the clam when it tries to open a half inch. I need to put the clam in the quarantine that I was going to use for the corals when they came in. I e-mailed the sender to delay shipment so I can use the QT for the clam. Is there any type of food that I need to feed the clam while in the QT? <Phytoplankton could be helpful, although I have heard that feedings are particularly important for juvenile clams. Your 5" Crocea is near full size and could probably live on very little food.> Or should I just let if feed off the light in the QT while it recuperates? <Depending on how long it is there will determine if additions are needed. Daily, small water changes from the main display could provide the clam dissolved organics to filter feed.> How long do I need to put it in the QT to bring it back to health before I put it back in the main tank? <You cannot put it back in the main tank until after the Flame Angel and Yellow Tang have been removed.> Thanks for all the help, Jeff <Good luck! -Steven Pro>

Clam Questions! Hi Bob, How are you these days!  <Fine> I have these weird encounters between my 4.5 inches clam that I bought last week who is moving and getting rid of the poor thing. Anyway! two days after I got the clam he was happy, in fact still is under the metal halide about 9-10 inches below the 175watt MH, lying between 3 rocks. The strange thing I saw was the snail (which I believe a somewhat related or maybe it is a turbo grazer type) (this snail also runs across the algae and suck on them clean), was attached to the clam. I decided to pick the snail and pull him off the side of the clam, man! I had to pull him really hard, which I thought what a good suction!  <Yes... good designs...> Today! I went home and saw the snail attached again, I pulled him off and it's even harder to pull this time, but the strange thing I noticed was the hard shell part of the clam had hole as if someone tried to drill a perfect hole.  <Perhaps "they" did> I know the darn thing is really hard, and can't imagine the snail would do this kind of thing! I'm afraid that the clam might die from this situation, because a year ago, I used to have 5 of those regular looking (round shape) turbo grazer snail, until I bought this strange looking one which he did the same thing attached to these snails, and died few days later. As a result I have tons of small snails (baby ones). I have 2 theory, 1 good and one bad. Lets start with the good one first, which is he thinks his trying to mate with his own kind!  <Nah> 2 his feeding on the clam, but how can that be if the snail feeds on the algae AKA vegetarians type.  <Things are not always as they seem... this animal may have a wider food preference than you assume> The mysterious part is how the heck did he put the hole through the hard shell of the clam? <A radula, odontophore... specialized structures like a rasping tongue and muscular apparatus for such boring... and secretions to aid in melting the non-living matrix of the shell... There are several groups of invertebrates with species that do this...> I thought I would go directly to the expert, thank you in advance, hope you have a good one. RL <You as well my friend. I would surely remove this snail. Bob Fenner>

Critters on Tridacnid clams... Bob, I have a question that I was unable to find in your book. Or any books I my library for that matter. After a recent outbreak of what I think was velvet, I removed all of the fish from my pseudo reef display tank, and put them in quarantine with some medication. The fish seem fine, but have one week of the recommended four left to let the velvet die in the main tank.  <A month at the minimum... two if all can stand it... and hope you have availed yourself of raising temperature and lowering spg... mid eighties and 1.018 or so respectively... to reduce virulence, speed the demise of the parasite(s)> I'm still in search of the source of the infection since we have not added a fish to the tank in 3 months, and yes we dip and quarantine all new members of the community! <Maybe the food? Contamination brought in from another system via a net, specimen container...?> The issue is the display tank. It is being over run by critters. Some are nearly shell less snails. "Limpets" or something like that. Others are small fast moving guys that skim across the sand and rocks. I assume they are Mysis shrimp or something like them. I have been "feeding" the two cleaner shrimp and soft corals to keep the biofilter running. <Don't sweat these... very likely innocuous, maybe helpful, and likely transient... especially with the reintroduction of fish livestock> None of the critter sightings bothered us much, we figured they had been there for a while and the fish had been feeding on them, particularly the six-line wrasse, P. springeri, P. fridmani, and neon gobies. We just figured the fish would have a feast when they returned to the tank. <Yep> Today, however, we found one of our clams closed up, when I picked it up, about 50 of the shrimp like critters scampered  away, and several of the limpets were on the shell. This leads to a chicken and egg question. Is the clam sick and the critters were attracted to the dying clam, or are the critters killing the clam?  <Hmm, too much likelihood of the latter to suit me... may be time to expedite the return of your fishes... at least the six-line wrasse.> We have two other clams in the tank, and while they seem to be irritated on occasion, they are open. The rest of the corals & polyps seem fine. I'm sure the fish will have a field day when they return next week, but I wonder if we should do something for the clam? Also, how do coral only tanks survive with all these critters? Are they a problem? Should we be concerned, or just marvel at the diversity of life in the sea? <By exclusion, through lucky mixes of other factors... I wouldn't marvel... I'd replace the wrasse.> On a lighter note, I love our tank so much, that I went and got scuba certified. We are thinking of going to Cozumel. Any suggestions? >> <A great place for new scuba experiences... fabulous clarity (regularly 100-200 feet) and the easiest drifting dive wall diving on the planet... lots of good operators there... Only real suggestion is to GO! Bob Fenner, just back from the Cook Islands and out to Mexico himself next week>

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