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FAQs about Giant Clam Placement

Related Articles: Got Tridacna? A beginner's guide to keeping Tridacnid clams by Laurie Smith, 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 Selection, Tridacnid Compatibility, Tridacnid Systems, Tridacnid Lighting, Tridacnid Feeding, Tridacnid Disease, Tridacnid Reproduction, Tridacnids 1, Tridacnids 2, Tridacnids 3, Tridacnids 4, Tridacnid Clam BusinessBivalves, Bivalves 2, Lighting Marine Invertebrates,

Crocea Suicide Attempt... Tridacnid placement f' -- 02/08/10
Hello folks,
<<Greetings Lanny>>
I just awoke this morning and checked my 30g/150w MH/54w T-5 that is in my bedroom. To my dismay, my Crocea had hurled itself off the rockwork and smack on top of some pesky Actinodiscus.
I am not so much worried about the sting as I am about the strange bundle still attached to his rock.
<<Mmm, yes'¦damage to the byssus gland can prove fatal>>
At first I thought it was the byssus gland, but as I read, it seems more likely the byssus fibers.
She seems alright...the foot looks unscathed and the mantle is expanding. I have included a pic of the bundle - my apologies for the amateur photography. Am I correct in my assumption that is it merely the fibers and not something worse?
<<From the pic it appears to be more than just 'threads''¦but if the 'clam initiated the move,' as opposed to being 'knocked off' the rock, then it is likely fine'¦though only time will tell. And as it should be obvious, the clam was not happy in its previous location. I think it unlikely this species was receiving too much light here, so do look for other reasons for its wanting to move (encroachment from corals/other stinging organism, too much/too heavy water flow, etc.)>>
Thanks for the help and all your great resources.
<<A collective effort'¦you're quite welcome>>
<<Cheers'¦ EricR>>

Re: Crocea Suicide Attempt... -- 02/09/10
Thanks for the quick response.
<<Quite welcome>>
The clam is in fact looking great today. The mantle is fully extended, and the portion that was touching the Discosomas looks unscathed.
The clam was contacting a Montipora capricornis in its original spot, but they had grown into one another maybe three months ago. Could that be the irritant?
The mantle would rest on the Monti when it was extended. I have never had trouble with Acroporids irritating my clams in the past so I thought nothing of it. This clam actually used to reside nestled into an Acropora colony with no evident nettling.
<<Though some have stated that these clams (Tridacnids) are very 'tolerant' of contact with other cnidarians, I have to think there is a 'limitation' to that contact'¦perhaps variable among the differing species and even among different specimens>>
I also wanted to inquire if the scutes that were broken in the fall have the potential to harm the mantle.
<<Sure'¦if jagged/sharp enough>>
They are sort of jagged. I hate to sound like a mother with a newborn, but I worry about all my critters.
<<There's likely little reason to worry, but if these breaks are overly sharp/pointy, you could remove the clam from the water (make sure it hasn't reattached to the substrate first) and try to file them down a bit with a 'fine cut' metal file'¦or better yet, one of those small fine 'diamond-grit' files used to sharpen carbide router bits and the like>>
I see too much slaughter working in the aquarium industry here in So Cal. Last week I saw a 6' black-tipped reef shark crammed into a tank at All Seas and it cut deep.
<<Sad indeed>>
Thanks again for the help.
<<Is my pleasure'¦ Eric Russell>>

Nano Aquaria; General Care, Tridacnids and Coral  1/20/10
Hello again Crew!
<<Hello Carla.>>
First off, kudos for providing an amazing resource and service to all of us in the aquarium hobby, and thanks for all your help in the past!
<<Thanks, I hope to you meet your expectations this time around.>>
I have a 29 gal. nanoreef tank that is currently stocked with inverts and corals- Tridacna crocea clam, frogspawn coral, rose Palys polyps, lots of Shrooms, some Zoanthids, and "volunteer" polyps from the live rock.
Livestock includes one peppermint shrimp, a purplish serpent star, one Astrea snail, and a scary looking hitchhiker crab (have not been able to id yet, but has a purplish-maroon rather smooth carapace and eight hairy/spiky legs... he's very shy so I haven't been able to get a good picture yet- will move him to a future sump/refugium if possible when tank upgrades allow so I can add a small fish or two without worry in the future- would hate to issue
him a death sentence unprovoked, but don't trust 'em for sure).
<<Agreed, until an identification can be made I would best assume it to be like it's cousins'¦.opportunistic.>>
The tank has been set up for quite a few years, and since being moved in July, has finally settled down again- lots of denitrification bubbles in the sandbed and worms and 'pods aplenty.
A friend of ours recently upgraded his tank lighting, and gave us his previous setup for a very good price- the tank was previously lit with two 65W power compacts. The new fixture is a 250W MH (I know, overkill...
<<Not if you want soup'¦.I'm kidding'¦.only a little. Seriously though, make sure you monitor the temperature for large swings, keep the pendant elevated a minimum of 12' and have a fan running across the surface'¦am I'm sure you're doing this but for everyone else out there in WWM land, keep a close eye on the evaporation. Nanos can swing quick and when they do it's not pretty.>>
but I hope the clam will appreciate the extra light) with 4 24W T-5 actinic bulbs. We have the fixture suspended about 8" above the tank (with an extra fan on the light timer to dissipate heat)- the fixture has a glass cover, and the tank also has a glass cover.
<<I should have read ahead..bad habit of mine, sorry.>>
We have the actinics on a 12 hour cycle, with the halide coming on 1.5 hrs after those for 8 hrs/day.
<<With what you have, you could do with 6 hours a day.>>
I currently have a double layer of plastic window-screen on top of the tank to dim the light until the animals can acclimate... my question is, is this a good photoperiod for our tank?
<<See above.>>
How long should we wait before beginning to remove the covering, and what's the best way to go about this (cutting back to single layer, and then none for parts of the day? how long between stages?)?
<<I would leave up both layers for about a week to 10 days, then remove one layer, then wait another interval of a week and remove the last one.>>
I'd hate to lose any of the corals due to burning- the clam in particular I've had for 3+ years and is the star of the tank- I'm looking forward to seeing his true colors again- had developed a rather brownish (though highlighted by blues and greens) coloration due to inadequate lighting before. Also (and this predates the lighting change by a good bit), the clam produces a LOT of byssal threads- is this normal? Looks like a spider web floating at the base of the clam that trails of 4-6" in the water column... I have searched for images of other clams that display this
but haven't found any.
Is this cause for alarm, or just the sign of a healthy clam?
<<Depends on where the clam is set in the tank, T. Croceas unlike their cousins tend to exhibit much more of a boring behavior, and prefer/should be on a nice rocky surface.>>
One last question- there is quite a bit of coralline algae on the front tank glass- I haven't removed it because I'm hoping to encourage more coralline growth on the rockwork- would scraping it off with a razor help or hinder the spread of coralline in the rest of the tank?
<<Neither, feel free to clean.>>
I don't mind the look of it, too much... but would be nice to have an uninterrupted view of the tank if it won't affect (or will help seed) the rock growth. We switched to all RO water for top-ups and water changes, which has helped the persistent nuisance algae problem quite a bit (I suspect phosphates and silicates in the municipal water)- Yay!
Thanks again!
<<I'll be moving on to your additional mail now.>>
**Addendum sent by Carla before first reply**
Also... the mantle of the clam is about 5" from the top of the tank (in the center), the frogspawn halfway down (also central, but far enough from the clam to be out of sweeper reach), and the mushrooms are mostly in the bottom half to two-thirds of the tank (those in upper regions are growing parallel to the light source and get more indirect light)... if it helps/matters!
<<No, same as above, sounds okay.>>
(bet you haven't heard that one a million times... right)
<<I have to admit, I've been here since 2003, been on the fish forums since 1999 and was a livestock manager for 3 years, and a volunteer at a public aquarium for 2 years'¦..and I've never heard that one haha. Good luck -- Adam Jackson.>> 

Crocea Clam Positioning -- 07/30/09
Hi Crew,
<<Hiya Debi>>
I have a Crocea clam in a 150 gallon saltwater reef and fish aquarium.
He has been there about a year and sitting on the rock ledge about halfway down a 24"deep space. I've never really been happy with where he is sitting because he attached himself turned sideways and was high enough up I couldn't really enjoy him (all I could see was the side of his shell).
<<Indeed'¦ These critters are best observed from 'above''¦mostly due to the way light refracts in the water, making much of the color and design of the clam's mantle muddy and indistinct when viewed from the side>>
Well, today I came home and he has for reason jumped off the ledge and was on his side on the sand at the bottom.
I have no idea why he decided to move
<<Hopefully, just not happy with its position/placement and not for more grave reasons>>
but now that he has I was wondering if he would be okay staying on the sand at the bottom so I can enjoy him.
<<I have seen many hobbyists place Tridacna crocea on sandy substrates, but this is not its natural habitat. This clam is found among hard/rocky substrates'¦often 'buried' in the rock itself which it accomplished through a combination of secreted compounds to dissolve the soft calcareous rock, and grinding of its scutes against the softened rock (this species is also known as the 'Boring Clam'). Also, being that this species of clam is not designed/natural to a sandy substrate, it may be more vulnerable to attack/intrusion of predators/parasites from 'below.' Even when placed low, it's best to put the clam on a rock rather than in the sand, in my opinion>>
I am just concerned about him having enough light there.
<<A valid consideration considering this animal's high light requirement>>
I have a Current USA Outer Orbit HQI + T5 HO + Lunar Light Fixture, 150 w that has eight T5 460 nm super actinic bulbs and three 14,000k halides. Is this enough light for the clam to have enough at the bottom?
<<Probably'¦if water clarity is maintained'¦though 10,000K bulbs would provide better penetration of more usable wavelengths>>
Also we changed out the Actinics a couple of weeks ago to the ones I mentioned above and they seem slightly more purple when they are the only thing on.
<<Perhaps a difference in make or spectrum (420nm vs. 460nm), or maybe just the difference in age/newness of the bulbs>>
I have my lights set to run the Actinics for one hour in the morning before the Halides come on and then the Actinics stay on one hour after the Halides go off.
<<Sounds fine>>
The halides are on for 12 hours daily.
I also have white and blue dawn and lunar lights for run accordingly. I would really like to leave this clam down low so I can enjoy him as he is very pretty blue and green. What do you guys think about leaving him on the bottom?
<<This is likely fine'¦but I would place a flat rock under the clam as explained>>
Debi Robinett
<<Happy to share'¦ Eric Russell>>

Maxima Clam Placement Angle  9/29/08 Hello again, <Hi Steve, Mich here.> I purchased a 2 inch maxima clam two days ago. <Tiny... not always the most hardy at this size.> The clam came securely fixed to a flat piece of substrate <Very good. Less of a chance to damage the Byssal gland.> I currently have 108W of 10,000K T5 (soon to be doubled) and placed the clam in the top 4" to 5" of the aquarium. <Be careful of light shock. I would place this clam low and gradually move up if need be.> At the height that I placed it and the height of my aquarium, viewing is a bit hard. <Move it down, at least temporarily.> So in my (possibly not so) brightest moment I stuck the substrate to my live rock at a 45 degree angle. <I'm worried that this will place additional stress on the Byssal gland. I don't think I would do this.> It is still receiving full light, is not shadowed and seem to be extending its mantle more each day, <If the clam is not extending it's mantle it generally is not happy. I would move the clam lower in the tank and see how it behaves there.> but my question basically is, does the clam have to be facing directly upwards if it was already attached to a substrate? <Mmm, no, but it will likely be happier if it is.> Thanks in advance and also for the wealth of info you guys and girls have provided <On behalf of Bob and the rest of the crew, you're welcome.> Steve <Cheers,

Re: maxima clam placement angle 10/8/08 Mich, <Hi Steve.> Curse the time difference! I'm in Australia. <Sorry! I'm in the getting very chilly part of the USA.> Was eagerly awaiting your reply but when I came home from work the clam had answered it for me. (it agrees with you.) <I'm sorry.> It was sitting half buried in the sand at the bottom of the tank with its previous substrate still at the top of the tank and still attached was what looked like its foot! <Likely byssal threads.> I removed the clam from the sand (it felt like it had already started to attach to the glass base, is this possible so quick?) <Yes.> and placed it back on the substrate it came with, this time level, mid height in the tank and with various bits of rock built up around it so it would stay put. <OK.> If it comes good I may just leave it in this position as it looks ok. <Just watch for mantle, hopefully you will get full extension, if not you may need to relocate yet again.> Can let you know how it goes if you like. <I would like, please keep me up to date. Hopefully I will be able to get back to you quicker next time!> How long should it take for it to re-attach completely? <Depends... can be quite quick to never.> Cheers <And to you!> Steve <Mich>

Tridacna clam sys., placement   12/12/06 Hi, firstly the WWM site is awesome! <Hello there James, Mich with you tonight.  Thank you for your most kind words!>   I've had my 50g tank setup for around 6 months now, with 75lb of live rock. The tank uses no mechanic filtration, purely live rock and a very good skimmer (Deltec MCE 600) to keep things clean! <OK > I have two Arcadia 54W T5 46" lights (Blue actinic and white), the blue bulb has a Kelvin rating of 2100K and the white is 9300K. <OK> I've been looking into getting what appears to be a Tridacna crocea, from all the pictures I've found. They are all around 1 1/2 - 2" in size. <Sizes do range, but small is OK.> I was thinking of placing the clam on flat spot I have close to the top of my tank (about 4" from the surface, with the lights another 2-3" above that). Would this be acceptable? <Yes, should be.> If so, would the clam be capable of attaching itself to the live rock, or do they require some form of substrate. <You could put it directly on the live rock, but I wouldn't recommend it.   This is making a relatively permanent commitment to the given location, as you will want to do all that you can to avoid damaging the Byssal organ (the foot) once it attaches. A better solution, in my opinion, would be to put the clam in, and I know how wrong this sounds in the karmic sense, another empty clam shell, or any other type of shell for that matter.  That way it can easily be moved and relocated if need be.      Thank you in advance! James. <You are quite welcome.  -Mich>

Re: Tridacna clam... placement   12/13/06 Hi, thanks for your swift reply. <You are quite welcome, James.  Mich with you again tonight.> I decided to take the trip down to my local marine aquatic store after reading your reply, I discussed various placement methods and we agreed that placing it on some form of movable platform would be best, but the spot I wanted to place it on (for maximum viewing potential/health of specimen) wasn't really suitable for that. <There are ways to modify.  You can temporarily place the platform on your sandbed and give the clam time to hopefully attach. (and adjust to the new lighting conditions)  It may take several days. Be very careful not to do any damage to the foot/byssal gland.  Hopefully the clam will produce byssal threads and attach itself to the platform.  Once the clam is attached you can secure the clam and the platform to your live rock by various methods.  Possibilities include: fishing line; zip ties; even gluing plastic golf tees to the platform and pushing them into the live rock.  This will allow you to easily move the clam so you can check on it's overall health and inspect for possible predators such as Pyramidellid Snails> So in the end I decided to go with straight to the rock, and figured I'm not going to be moving it around and if I do need to I could always move the whole rock (not ideal I know but it's workable). <I would urge you to reconsider.> So now I'm the proud owner of a Tridacna crocea (I hope!) clam :) There should be a picture attached. <No attachment was received. -Mich> Thanks again, James.

Crocea Clam...Shell Going Soft - 09/28/06 Dear WWM, <<Dustin>> I have a 240 gallon reef tank which is 31" deep.  I have three 400 watt metal halides  (2 at 15K and the middle bulb at 20K).  I have a Crocea clam nestled in the sand bed at the bottom of the tank. <<Mmm, prefers a "rocky" perch.  A common name for this species of Tridacna is the "rock boring clam."  These clams exude a substance that softens carbonaceous material/rock, then by "squirming" about, they can actually bore in to the rock.  Not only is this more natural for the clam, but this action serves to protect their vulnerable byssal opening from predators/pests>> The clam seems to be doing fine but I noticed that the shell of the clam looks as if it is eroding. <<...!>> It is like it is turning soft towards the upper edges near the mantle. <<Can't be good...>> If I touch the shell it is soft and it just brushes away. <<Yikes!  Have never encountered this...pH/calcium/alkalinity are where they should be in this system?>> The clam still opens up but am not sure what could be wrong with its shell. <<Nor am I...>> My bulbs are only 3 months old and are still very bright. <<I don't think this is the problem>> Could it not be getting enough light? <<Something in the 10,000K range would be better in my opinion...but yes, it is likely getting enough light>> Or insufficient calcium. <<Mmm...just musing here, but I wonder if maybe something is keeping this clam from assimilating calcium from the water column?>> I have checked all my water parameters and they are all in sufficient range.  Maybe a fungus of some sort? <<Another possibility I suppose.  If so, I don't think there is much you can do as any treatment is likely to kill the clam>> Thanks so much, Dustin LeCave <<Wish I could be of more help...perhaps Bob/somebody else has seen this before.  Eric Russell>>

Relocating Clams/Dealing With The Byssal Attachment - 08/26/06 Crew- <<Craig>> A quick question: <<Alrighty>> I have had a Maxima in my system for about 10 weeks now, and it seems to be doing fine.  However, once a week or so, I will come home and it will be laying over on its side. <<...?>> When I first introduced the clam in QT, it picked up a small piece of rubble from the sand bed. <<Ahh...know where this is going...>> This piece of rubble does not cover the byssal area entirely, but the clam 'thinks' it has secured itself when in reality it has not. <<Indeed...am very familiar with this scenario>> Short of jamming it into a crevice, is there anything I can/should do to get it to let go of the little piece of the rock so it can attach to a more substantial piece? <<There is, yes.  Remove the clam from the tank and using a sharp knife with a pointy flexible blade (a fillet knife works very well), "carefully" pull on the stone stretching the byssal threads just enough to get the tip of the blade in to "cut" the threads.  Cutting the byssal threads does the clam no harm...but do be attentive/diligent when doing so, so as to not cut or tear the byssal gland (this often proves fatal).  I have done this procedure time and again when relocating clams (can be done "in-tank" with adequate care) or to resolve the issue you describe, without a single loss related re>> Craig <<Regards, EricR>>

Clam Placement - 02/27/06 WWM Crew, <<Derek>> I have a 29 Gallon with a 150w SunPod on it and a 2" Crocea, I originally placed him about mid way up in the rockwork, but all my "sessiles" took to tormenting him. <<?>> I've moved him to the bottom of the tank on a hard rock buried in the sand - he's been safe ever since. <<Ok>> It was an easy move since he never attached himself to the upper rockwork, he seems well settled, but I'm wondering if the lighting is good at that level - tank is 18" deep and there are no obstructions to the light and he will have plenty of room to grow to full size.  Are we in agreement here? <<We are...this light with this tank depth will be fine for the clam.>> Derek <<Regards, EricR>>

Clam Lighting & Placement - 12/17/05 Hello again! <<Howdy!>> Just had one other quick question I was hoping the crew at Wet Web could answer. <<I shall try.>> Is a Coralife Aqualight Pro 1-150 watt HQI/ 2-65 watt compact actinic fluorescents/lunar light fixture adequate lighting to do SPS and clams?  I have 46 gallon tank, 18 inches deep w/ mounting legs 4-5inches above tank. <<Should be fine.>> If so, could a clam on two inches of substrate in full light thrive or does it need to be higher up? <<This lighting would be fine for a clam at this depth.>> Thanks again for any help you can give.  This subject proves to be quite confusing. Thanks, J-Man <<Maybe this will help:    http://www.wetwebmedia.com/ca/cav1i3/Clam_care/Clam_care.htm >> <<Regards, EricR>>

T. crocea Lighting and Placement  11/30/05 Hi, <Hi Dustin.> I have read though most of your articles and learned a ton of information for when I set up my next tank, but in the meantime, I have a few questions that I could not find answers to. <Ok.> I would like to purchase a T. Crocea Clam (~1-2"),  <I would go for one in the 2+ range maybe even a little larger.> and have a question about the lighting. I currently have a 40g tank, that is 36"x18" x 12" deep, with a 175w 14000k MH light 5" from the surface of the water, along with 3 - 24w 6500k mini-PC's, and a 65w 50/50 ( ? 10000K, ? Actinic) PC. The MH is in the back-right side of the tank, the 3 mini-PCs are in the back-left side, and the PC is along the front of the tank. I leave the MH and mini-PCs on for 11 hours a day, and the PC on for 15.5 hours a day. I currently have 2 hammer frags under the MH and 4 candy coral frags under the mini-PCs. The hammers open up more than they did at my LFS, and the candy coral seems to be doing OK, although the heads aren't opening as much. <I don't think the lights or to blame for that, the PC's are efficient enough for this specimen, maybe water flow?> My questions are: 1) Is 14000k MH okay for a T. Crocea clam, or should I buy a 10000k replacement bulb? <I would rather see 10,000K for this specimen.> 2) Where would the best placement for this clam be (which area of the tank, and at what elevation)? I would be inclined to say at mid-depth under the MH, but I hear they need a more full spectrum (mixture of my bulbs). <I would place it in the rockwork, upper ? of the tank as close to the MH bulb as possible. T. Crocea is the most light demanding of Tridacnids. Also as far as spectrum, most animals hosting zooxanthellae prefer Kelvin ratings of 6,500K to 10,000K. Actinics and bulbs in the 15,000K to 20,000K are mainly for aesthetics.> 3) Is my MH lights left on too long (11 hr/day) for this clam? (I read here that some people leave theirs on for 6-8 hours per day) <11 hours is a bit long, I won't say that it will hurt the clam but it is unnecessary.> <<Where did these clams evolve?  The equatorial tropics.  Anyone know what the photoperiod of equatorial regions is?  12 hours of light, 12 of dark.  The goal is to mimic natural conditions.  Marina>> 4) What lighting is best for the candy coral? I have read that they do not like direct MH lighting, so I placed them under the mini-PCs, IYO, what is best? <There placement as far as lighting needs appears fine.> Thanks, and keep up the good work <You are welcome and thank you.> Dustin <Adam J.>

T. crocea Placement  10/3/05 Hi Bob, <Actually Adam J here with you tonight.>             Leaves are turning up here in Utah and winter better be getting a move on cause' we're tired of waiting.  <Lucky you were dealing with fires here in SoCal.>  But more to the point, I have a couple of questions I'd like to ask if you don't mind.  I just bought a crocea clam from my LFS and they helped me as much as they could with the dilemma of my first tridacnid.  <Well it's a little late now but T. Crocea is not the best choice for a first Tridacnid.>  I was told that one of the hardest parts of acclimation is getting them to stay at there spot.  <Croceas are the boring clams, (as in they bore into the rock not put you to sleep)  From time to time they do have trouble attaching their byssal foot and fall over.  They should be placed in the rock facing upward, as high as possible as they are also the most light loving of Tridacnids.> They told me to start on the bottom and move up.  <Why? Is your light significantly stronger than the system from which the clam came?  Its best to pick a spot for Tridacnids and leave them be, moving them around is a quick recipe for demise.> But they did tell me not to wedge them because then they can't open. They said just keep putting them back up-right. I'm thinking there has got to be an easier way.  Is there?  <Place it on flat surface in the rock work in an area of strong light and moderate flow and leave it be.  The sand really isn't a great spot for the if that where it is. > He will be on the bottom for a couple more days until he moves to his final resting grounds towards the top of the tank. Any advice would be helpful. Brian <Adam J.>

Removing a clam from live rock 6/13/05 Hi Crew, I purchased a  2" Crocea Clam about four months ago and placed him into my 90g tank.  Since I am running PC lights I decided to place him higher in the tank on a piece of live rock to give him better light exposure.  Well he looks great and is definitely growing.  I placed him in a crevice which he is now filling up and I am afraid that in another month or two he will grow too large to open and close.  I have tried to gently remove him from the rock but he is holding fast.  Since he is in a crevice I cannot place anything underneath it to try and gently pry him off the rock.  How in the world am I going to get him to let go of the rock without tearing his foot?????  <You can probably leave the clam where he is.  One of the common names for T. crocea is the "boring clam" for their ability to rasp through rock.  You could also remove the entire rock from the aquarium and use a Dremel tool to widen the crevice.  As a last resort, you could cut the whole rock apart or slip a flexible tool into the crevice to cut the byssal threads close to the rock.  Best Regards.  AdamC.> Stung Clam? I bought a couple of clams a couple of weeks ago.  One is a Derasa and the other a Maxima. I put them on the sand bed with a rock slightly burying beneath them.  They are under MH lighting and I feed DT's Phytoplankton to the tank.  The other evening a branch of my Hammer Coral dropped onto the opened Derasa. <Oh!>   The clam still opened ok that evening but not as much the next day.  Now today it is closed tightly.  My guess is that it is suffering from stings from the Hammer Coral.  Am I on the right path or should I be looking at something else. <This is likely it> I have not seen any snails but I did see what appeared to be tiny black specks (like copepods only black) dotted about the shell.  The Maxima is doing fine and that's why I believe it was because of the Hammer.  Is there anything that I can do here?  Thanks Brad <Not much... do make sure the Euphylliid is securely anchored... away from the Tridacnids. Bob Fenner> Clam purchase/placement and "screen method" 7/10/04 Hello to all, <cheers> I have a question concerning clams. I have been reading D Knop's book on Giant Clams and I am confused on two points he makes that seem to contradict themselves. First the book states to pick a good location and leave the clam there as moving the claim can cause stress and death. <this is very true for most any photosynthetic reef creature you will find (corals, clams, anemones, etc). Moving them frequently is a tremendous stress and can kill weak imports> Then it later says when clam is acclimated to place on the bottom and gradually move to higher positions to slowly get adjusted to lighting?   <this is also true. The difference is a matter of weeks/months versus days. All newly imported clams (corals, anemones, etc) are at potential risk of light shock from the extended transit and holding on import in darkness or dim illumination (many days). Thus its best to be conservative and place all in low or moderate light situations and leave them alone for at least a week several would be best). Feeding and nutrients will compensate for the lack of light in the meantime. Then... after several weeks to a month... the clam can be slowly moved up the reef if it is a species/variety that needs brighter light. A healthy shortcut to this methods is the "screen method" (use that phrase in a search on our homepage wetwebmedia.com - there's a google tool waiting for you). The gist of it though is to put the clam, coral, etc in what will be the final resting place in the tank however high that may be. Have some fiberglass fly screen (plastic hardware cloth) cut in sheets (a dozen or two) that are a size slightly bigger than the new clam/specimen. Place this stack between the lights and the water surface (on the glass cover or a rigged pair of rods) to cast a shadow over the new/weak specimen. Then... every other day or so, remove a sheet of screen so that after some weeks, the clam is very gradually adjusted to the new bright lights> I do not wish to spend 80$ just to do the wrong thing. <the "right thing" do in all cases is place all new animals (anything wet really... plants, algae, sand, rock, corals, fishes, snails... everything) through a proper quarantine period. It is the recommended, if not responsible/ethical, thing to do. Otherwise... every new piece you add to the tank is like a spin on the chamber of a gun - you are playing Russian roulette with the chance of introducing a parasite, pest, predator or disease in tot he aquarium. If you do not heed the need for QT... you will eventually get burned... at the expense of creatures lives likely so.> Any advice would be helpful. BTW I have 3 DI 250w MH lights 13" above my 180g tank (27" from bottom) would a T. maxima live on the sand or would it be better higher up. Thanks, Mike <it can definitely live on the sand under these lights (but still bury a rock underneath it to protect it from predation). Anthony>

Tridacnid placement and attachment - 4/15/04  Greetings!!!  My 5 inch clam (not sure which 'line' of measurement one is to use) did great for a week and was even hosting a yellow coral goby....At first, the goby would rarely perch in the clam but as he and the other 3 yellow coral gobies were still determining their territories, one goby choose the clam....Pretty much as soon as the goby fell in love, the clam got cold feet (or so it appeared).  I barely had basic knowledge of clams before I got one....bad me.....<Yes. Especially with clams. They do tend to be temperamental>  I recently learned (on your site) that clams must be placed on a flat rock to attach and be safe from predatory worms and others. <Well, yes but not as much for predators as for falling down and stability> I specifically designed my 80 pound reef to be void of flat rocks. The clam was merely sitting in the rockwork toward the back. After pondering whether or not my local fish store had 'aquacultured' him onto such a rock for my convenience, I decided to pick up the clam and get a closer look underwater with the intention of moving him as well because he wasn't opening fully anymore. I also thought that the move may sway the goby to lose interest. <Aquaculture is usually in reference to farm raised oceanic creatures not as a means of attachment. In any event it is fairly easy for one to get a piece of PVC and cut it in half lengthwise and sit the clam inside. Overtime (usually a few days to weeks or months) it will attach. I have not had any trouble with my clams without attachment. The main thing is if it is to be placed in the rockwork, be sure it cannot fall down. It is more important for proper lighting, food sources (usually phyto and detritus), and the lack of any parasites (Pyramidellid snails) take a look at our Tridacnid FAQs>  Since I have no flat rocks at the ready, I placed him in the sandbed at the front. <A good idea if you have good lighting> My sandbed ranges from 5 inches to 1 inch in some parts of the front. I placed him in 1 inch of sand with his 'butt' touching the bottom of the tank in hopes that he might 'attach' the bottom of the tank since it is flat. <Oh....a good idea> In one of your clam FAQs it says it could take a year for an unprotected clam to be attacked and killed. <I would be more worried about the clam dying of a lack of lighting, water parameters, and nutritional requirements before predation> I'm sure it could take a lot less time than that too depending on 'luck'. <True but there are greater worries to be had. Especially in acclimation of the clam(s) to your tank specifications> For now, I'm hoping the clam has 'time' to attach to the actual bottom of the tank. Any thoughts? <See above>  My tank is 55 gallons. Just got brand new bulbs 2 weeks ago for my 2 96 watt pc.s (1 actinic). 15 hour photo-period. 2 hours of direct central California sun (usually). Take has been going for one year. I'm a heavy feeder. It's a Zoanthid tank, and I know clams are usually found associated with stony corals, do you think this has anything to do with the clams discontent or is it definitely the goby? <Likely the goby> The gobies have been in the tank for 2 or 3 weeks and the clam has been in for maybe 11 days or so. My tank has a 35 x full volume per hour turn-over rate. No sump, but 7 powerheads. No heater in the summer. Nitrates undetectable with "Aquarium Pharmaceuticals" test kit. <Gobies have been known to disturb clams to death. They don't always do it on purpose but it has been known to happen. Read more about Tridacnids in our FAQs: http://www.wetwebmedia.com/tridacnidart.htm >  Thanks WetWeb! I luv ya! <Thanks for being part of it all ~Paul>

Tridacnid Crocea Placement near my LTA Hi, <Hi there!> I recently added an LTA to my 120G Reef.  I placed it at the end of my tank hoping it will stay away from my corals.  Will the LTA pose a danger to my T. Crocea clam?  As you can see from the picture, it is 1-2 inches away.  I also have a Frogspawn coral and Hammer coral at the other end (4ft away) of the aquarium.  Is this ok or am I susceptible to Chemical warfare as I have read about?  I also have an Elegant Coral ( 2ft away on the other side of the rock work) and a Moon Coral 6 to 8 inches away? Is this ok? <I don't foresee any problems in terms of chemical issues or placement, but do be prepared to move any animals that are interacting aggressively toward each other (particularly the clam if the anemone expands to contact it).  Your "Moon" coral is capable of producing shockingly long sweeper tentacles.> Is it also normal for my Cleaner shrimp  to be walking on my LTA?  He does not seem affected by the LTA's sting. <It seems very weird, but it is fine.> thank you very much, <Gladly. Adam> Jo & Christine

Clam Lighting Questions Dear WWM crew, I hate to make a nuisance of myself, but I have a couple more questions (several of them are probably stupid, but, hey, I won't know if I don't ask, right?) <Truly, the only stupid question is the one not asked!  Especially if lack of asking kills animals.> I went back to the store, and the Crocea was gone (big surprise) but they now have a beautiful purple maxima for the same price.  I was talking about getting it when a friend and fellow reef keeper jumped down my throat for dooming a clam to certain death by trying to keep it under VHO's when all clams MUST have MH. <Tell your friend to settle down and "don't believe the hype!"> He even pulled a reef-keeping handbook off the store shelf at random (hardly the most responsible method, I know) and showed me that it says they require MH.  Even your own FAQ's seem to mention MH a lot.  But then other articles say they can be kept under normal fluorescents!  I know it has a lot to do with depth and distance between bulb and water, but aren't there some sort of guidelines?  Can a med-large purple maxima be kept under VHO's? <MH is certainly recommended.  As a general rule, the more light they get, the better clams do, however, as long as you exceed their minimum requirements, they will do fine.  Growth may be a bit slower, but they will do fine.  In your tank, under 3xVHO's, I would certainly keep a clam in the upper 8-12 inches.> In the same vein, I also looked at (and ended up purchasing) the most beautiful Frogspawn/Octobubble I have ever seen.  It had been there for a month, under 3x4' VHO's, and was doing great.  I also know your website says these corals need moderate light and current, and I would have thought my system about perfect, but again, my friend and his handbook both insist they require bright MH light and very brisk current. <The level of reef keeping has been raised since most current available references were published.  What was considered brisk current then, would be moderate at best now.  Your system sounds quite ideal for Euphyllias.> I must admit that I've not had luck with these before, but after reading your website, I was thinking it had more to do with the large numbers of soft corals (many of which I have removed to their own tank), and not inadequate light.  I placed the Frogspawn at the opposite end of the tank from the overflow/return, about halfway down.  It gets good indirect flow but no strong direct current.  Does that seem reasonable? <Sounds very reasonable.  Overly strong current will prevent the coral from opening, and you certainly have plenty of light.  Euphyllias are quite sensitive to water quality in general, and the presence of soft corals in particular.  Water changes and carbon will help ameliorate these effects.> One thing I would find extremely helpful is if your descriptions of each coral/clam/animal said something about light/current/placement requirements. I know that I read something about different clams having preferences between rocks and sand in the FAQ's somewhere, but now I can't find it, and the species descriptions don't say.  Same for corals. <Any clam or coral can be kept on the sand as long as it can't bury itself.  As a rule, Crocea, maxima and Squamosa clams are rock dwellers, but all can be kept on the sand as long as they get enough light.> Okay, I am sorry for the length, but I have two last questions: <No worries!  Ask away.> In your descriptions of placing VHO tubes 3-6 inches above the water, I am assuming this is without a glass canopy in between?  I still had one on my tank until recently.  I grew up with them and never really thought about removing it until I was thinking seriously about lighting. <Give up the glass!  Glass covers really do attenuate the light a lot, particularly if they aren't very clean.> Second, does my colt coral pose a major chemical warfare problem, or is that mostly a leather coral issue?  Can I keep just a few green star polyps and/or frilly mushrooms in my reef tank without doing any harm, if I thin them regularly? <All softies will produce allelopathic chemicals.  Sinularia (finger leathers) and mushrooms are among the worst.  Your colt and star polyps are more dangerous in direct physical encounters.  When you rule out all other causes of ill health in a coral and suspect chemical warfare, you will have to remove the aggressor or the victim.  In the mean time, keep up the water changes and frequently changed small amounts of carbon.> Thanks again for all the advice and help.  Jim <Glad to!  Adam>

Clams and rocks Bob how deep do you put the rock under the sand when you put the clam over the top of it?    RGibson <heehee... you engineering guys over think everything <G>. The clam is not to be buried far to begin with... and the rock used to protect the byssus of the clam can be very small... just big enough to cover the footprint of the clam. It could even be a small piece of ceramic tile. Even a larger rock though is buried in the sand just the same. If its easier... let the clam attach to the rock above sand first before burying both. Kindly, Anthony>

Clam likes to be on its side? Nope! Hello Bob, Anthony, Steven, and the rest of the crew: <Whassssup, dude?>> I have a ~3" blue t. maxima purchased on July 4th. After acclimating him, I placed him onto an old Trochus shell so that he could attach his byssal muscle (?)  <very wise> and oriented him upright (Trochus shell buried) on my DSB, 19-20" under 2 175w MHs (+ 130w supplemental PCs).  <reasonable> He has remained fully open and responsive to movement since the 2nd day. I have found no parasites. However, he tends to roll over onto his side, pulling the Trochus shell out of the sand (I righted him once and he rolled back over within 24 hrs.). His byssal parts are protected by the Trochus shell but I am worried if he is getting enough light laying on his side. Is this ok? <nope... very harmful even after only a few days. Reposition as before but put a small "campfire" of live rock rubble around it temporarily until it settles in. These clams live buried in rock (!!!) naturally and wild ones are broken out of it. They need to feel secure. After a few weeks you can pull the rock rubble away> Also, I have found mixed advice on the depth. Some say that this is ok, others suggest moving him higher into the rockwork. So far I am leaning toward leaving him in the sand, but what do you think? <eventually a little higher, but for now leave it be to acclimate properly. A move will only stress it more> Finally, just for reference, here are the steady parameters in my 72g tank: temp: 80, SG: 1.025, pH: 8.3, Alk: 4.0 meq/l, Ca: 400, no nitrate/phosphate. Btw Anthony, I received my copy of your coral propagation book and have enjoyed it very much.  <thank you my friend!> I have been employing your digital pH/CaOH "slurry" method along with dKH buffer and my pH, alkalinity, and calcium levels have really stabilized nicely.  <excellent... it is indeed an amazingly simple way to dose Kalkwasser and enjoy its many benefits> I emailed a while back about a frogspawn that has grown anthocauli (?) on a previously dead branch and the growth is continuing at a substantial rate. Still trying to get good photos.  <outstanding... yes please send pics of the buds> Too small for a digital camera for now. Ed Marshall, Austin, TX <see you at MACNA in Dallas/FT Worth in September <wink> Anthony>

Crocea clam tipping Hi, I e-mailed you last week about the Crocea clam that I bought when I was down in Indy and while I was there the attendant suggested I "burp" the clam I already have to see if there was already any air in it or under it that would keep if from extending its mantle. You guys got a good laugh out of it as I knew you would.  <yes, my friend... I recall. Thank you :)!!!> I didn't think there was any validity to "burping" a clam.  <heck... I'm just grateful that the LFS attendant didn't have a proctological fixation> Actually the one that he picked up and "burped" right in front of us looked pretty pissed off when it was "burped" for instructional purposes.  <heehee... imagine how it would have reacted to the anal probe?!?> The crocea is now in my tank under my now (4) 160watt VHOs instead of the 6 that I had and also the 400 watt MH. It is on the bottom in the sand and I am told by you fellas that he/she is getting plenty of light and I agree. The problem is that the clam is tilting himself to the side. I have tried to prop him up against a small piece of live rock and it is still wanting to tilt.  <Ahhh... first mistake (possibly): all clams MUST be set upon a flat rock even if it is buried in the sand. Else you can count on a worm, snail or crab crawling up the byssal port and killing it within a year. A common mistake with clams> Should I keep trying to prop it up so it is oriented toward the light or should I just leave it be for the first couple of weeks until it is used to the lights and the conditions? Any help would as usual be appreciated.  <after placing the clam on a small flat rock on the sand bottom, put a temporary "campfire" of rubble/rock around the clam to keep it supported and upright. Within 2 weeks it will set new tissue down upon the flat rock and stay upright. You can remove the surrounding rubble then> Thanks, Jeff <best regards, Anthony>

Re: Crocea clam tipping Hi and thanks for the re. I noticed when placing the clam in the tank that it already has a piece of rock attached to its byssus threads on the underside and this is why I felt it would be OK to place the critter on the sandy bottom.  <agreed> I wanted to gradually acclimate it to the lighting by putting it on the bottom and because this is the only spot available in the tank at the moment.  <indeed best to acclimate most clams and coral on the bottom of bright/halide lit tanks first> Should I build a fire around it in the meantime and make sure it is oriented toward the light?  <yes, my friend> Thanks, Jeff <best regards, Anthony>

Clam Moving Anthony, <cheers, Mark> I purchased a 8" Derasa Clam from a private individual that is selling his tank. The clam was in his tank for over 2 years and looks very healthy. It appears that the clam is trying to move, since I keep find a hole in my sand bed at his base. Water quality and flow is good, my calcium is at 380 and climbing (new reactor). I originally placed him in the center and have moved him to one side and still the same. I am assuming that he's not happy with his location or does this indicate something else? <not an indication of anything bad at all. Any clam relocated may be inclined to shift, settle or even move (over a distance... crawling slowly with their muscular "foot"). Simply a matter of getting settled. In aquaria, however, this and any clam really need to have a flat rock under their shell to attach byssal threads to for security and protection from predation (worms, snails and crabs entering here. Still best to also keep big clams on the bottom for growth/safety. The compromise here is to bury a small flat rock(s) slightly under the sand for the clam.> Thanks, Mark <best regards, Anthony>

Is my clam doomed I have recently acquired a 2" derasa clam. He was 10" under 200 watts of Smartlight. Last night he jumped down a step on my live rock, but he left behind some white tissue still attached to the rock above (byssal (sp) tissue?). <correct> Is there anything I can do or anything I should look for Thanks Jeremy PS other than this he appears to be in good health <no worries at all... clams commonly abort old byssal tissue. It is generate new at the new point of attachment. Freshly imported/disturbed clams will often do this. Probably just fine. Make sure it attaches soon for its own good (protection of byssal port from crabs, worms, etc. Anthony>

Light on Clam would 200 watts of CSL Smartlight be enough light for a small clam (maxima) on a 55 Gal tank??? Thanks Jeremy <yes...very fine, but do be sure to keep clam within top 1/3 of tank for best success. Clams really do enjoy bright light, and fluorescents do not penetrate deeply in water. Kindly, Anthony>

Squamosa clams dancing the Irish jig <Anthony Calfo preparing myself for the upcoming trip to Germany...eating sausage casseroles, sausage omelets, sausage pie and sausage milkshakes...with a sauerkraut garnish. All washed down with warm dark beer. Nobody light a match!> Hi again!  <Salute> I have 2 squamosa clams that just will not keep still.  <when you've got a good song in your head, it is hard to resist finding a groove... cut them some slack, my friend> I place them on a flat surface and the next morning they are on there side or on the sea floor, I have more than enough lighting ( I am the guy who is making lava in his tank)  <Ahhh, yes... I remember... 400 watt halides over 2" of water... making steam. How you 'doing?> my T. Maximas are all doing fine and staying put.  <like deer in 400 watt headlights...heehee. I'm just joking of course (thanks for being a great sport...and target <wink>). High intensity lighting is very appropriate for T. crocea and T. maxima clams, in particular> I don't understand there fully expanded taking in all the rays I give them but they keep moving. Someone said to me you better move them from that spot cause they aren't happy.  <nope... I disagree. As much as I enjoy teasing folks with big watt MH on aquaria less than 30"... too much light is not your problem in this case. I had the pleasure of having two XL squamosa clams (12-16") spawn in my greenhouse. They were in full sun with barely two inches of water above them and supplemented with a 400 watt halide (ahem)> Well I have moved them to other areas of my tank and I still get the same results.  <Aiieee! A good way to stress/kill symbiotic animals. Never move photosynthetic reef inverts even twice in one week through different light intensities...especially when new (having been imported and run through 2-5 light intensities through the 1-2 week chain of custody on import). Very stressful for the animal to compensate for especially if their fatty storage is low.> Currently now I have one in the sand and the other on a ledge where I have a blue Staghorn coral. so, tell me what can I do just leave them be??? <best if placed on a piece of rock to protect byssal port from predation by segmented worms, crabs and especially (although not foolproof) Pyramidellid snails. The chap on the sand can simply have a flat rock placed under it and buried in the sand. I'd actually place both clams on a flat rock in the sand. This will leave room for maximum growth for this species the third largest Tridacna species. Reaching 18" in well under ten years. Plan for this kind of growth. They are moving because they simply want to be lodged in place in case of a storm (that will never come in your tank)... kind of. Once they are where you would like them to reside, place a temporary campfire of rock rubble around them to hold them in place. After a few weeks of being unable to move or tumble, they will set byssal tissue down to the rock under them... after which you can remove the rubble campfire and better enjoy them aesthetically. Kindly, Anthony Calfo> Tired of moving......... Walter

Clam attachment Dear sir: I am having trouble getting my new squamosa clams to attach to some pieces of  rock. They were getting knocked over but now they are in their own tank.  What can I do to get them to attach and more importantly to prosper? What  are their food and water quality requirements. I must admit I don't know much  about clams and I am trying to have better than trial and error success. I am  very successful through the years with fish and soft corals. I even breed  maroon clowns. Not that it matters. Thanks, Bevan Cotton >> To further Tridacnid growth, attachment, health in general... Keep biomineral and alkalinity levels up... periodically feed algae cultures or introduce algae foods (from paste, frozen, dry sources), hook up a refugium, mud/muck filter, add some (more) peaceful fishes whose wastes, movement will add to the clam's well-being... Bob Fenner

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