Overextended clam?

[LCDRDATA]

We bought a croseus clam for our 75 gallon setup at the end of August. We knew it had to be fairly high up in the tank to get enough light. It didn't seem happy the first 2-3 places we put it - we kept getting up in the morning to find it "face down" on the bottom of the tank after it had let go and fallen off of where we'd placed it. It's been where it is now for a couple of months, though, so I think we've solved that problem.

However, we noticed early on that the mantle was extended much farther out than we'd expected. It's something like 3-4 inches beyond the edge of the shell:

Is this normal, and if not, why might it be doing this? We're feeding it regularly with DT's phytoplankton, and water parameters are good (we've just been through a nitrate spike, but that seems to be over, and there was never any difference in this regard before, during, or now after). Any insights are greatly appreciated!

 

[tmcgaughey]

great question.. i'm along for the ride

 

[Reef Newb11]

What lighting do you currently have? it could be that the clam is reaching for more light. You could try placing a small flat rock underneath the clam and get it to attach to that then you should be able to move it higher up and hopefully he wont keep jumping off.

 

[LCDRDATA]

The current lighting is two twin 48" T5s - one has two 10,000K (I believe) bulbs, the other has one 10,000K and one actinic. The 10,000Ks might all be 14,000Ks, but it's definitely one or the other.

We thought about trying to place it higher, but it's within 5" of the surface as is, and there didn't seem to be anyplace more than about an inch closer to the surface - the one place that was higher was the second location we tried, only to find it face down in the sand the next morning.

If it ever lets go of its current location (it has shifted an inch or two since being placed) we'll try to get it anchored to something we can then move, but I'm very hesitant to try to pry it off of the rock it's currently anchored to.

Here are a couple more pics; although they're not the greatest quality I think you can see what I'm asking about:

But I understand that it may be looking for more light. Are there any other possibilities?

 

[Lenny718]

In all my years in the hobby I never saw a clam extend so much, I will also be tagging along to find out.

 

[E.intheC]

I'm along for the ride as well.. hopefully the clam will be okay!

 

[tmcgaughey]

sounds like you need a bunch more lighting
that doesn't sound like much for a clam at the bottom of your tank

 

[jedheuer]

Hi,

Not an expert here but I have had a similar experience. I would guess that you you have too little light for the clam and it is hyper extending in order to compensate for the lack of light.

I have a clam that looks almost exactly like yours. I run 36" 8x 39w T5 HO 10,000 K bulbs over my 40g tank. The clam sits on a rock on the sand 16" below the lights. I placed a peice of eggcrate over the tank to keep some clown fish from jumping out and that reduced my light somewhat. The clam started hyper extending exactly like yours and now is bleaching around the edges of his mantle. I removed the eggcrate and will change the bulbs if the clam doesn't recover soon.

Based on my experience with 8 x 36" t5's, I would think that you need much more light than 4 t5s over your 75 for your clam.

Best of luck, you've got a nice clam there!

 

[LCDRDATA]

So far it looks like three votes for more light - any other ideas? Do you think it's just light, or light and some other factor? In the meantime, as a stop-gap I have a 26W 6500K compact fluorescent in a plant light spot fixture and I'm putting it directly over the clam - we'll see if that helps while working on a more permanent solution.

Given the way our tank is set up, the most straightforward options to boost light would be either what I've just described, some kind of more powerful/focused spot lighting, or an additional twin 48" T5 fixture. If I go with another twin T5, those come standard with one 10,000K and one actinic - would that be enough or should I swap out the actinic for another 10,000K bulb? On either my current setup or adding a third twin, would it make any difference if I went to 14,000K or 20,000K bulbs vice the 10,000K? Metal halides aren't an option, as they literally give my wife migraines - just something about the light quality.

In terms of potentially moving the clam closer to the top of the tank - not easy as we'd need some serious rearranging, but better that than losing the clam - how can I get the clam to let go of where it's finally anchored without just ripping it off? To reverse the phrase, I don't want to add injury to insult.

The clam and I are waiting for even more of your good inputs - Thanks!

 

[phish guy]

do not by any means, rip the clam off. that will most likely kill it. i have heard that cutting the byssal threads with a brand new razor blade will work, but check out the clam forum first.

your clam is definitly reaching for more light. i would definitly say get more light. 4 T5s on a 75 is not enough. at least double your light. try mixing up the bulbs too. go to the equipment forum and see others configurations for their T5s, there are alot, lots more than just 10000ks and atinics.

 

[jmadison]

I agree more light, way more light.
Get a mixture of spectrums too, ask grimmreeper in the t5 forums
You can cut him free with a scalple or razor, just try to cut as close to the rock as possible.
Are you target feeding with phyto or just adding to the tank?
What are your params? Temps? Light schedule?

 

[jedheuer]

Defiantly stick with 10000 K bulbs, dont go higher or add more actinics. Clams need high PAR output which roughly speaking starts to go down as you go to a higher kelvin. Actinics also have little PAR. if you like a blue look that your actinics provide you can get 10000 plus blue, which actually put out a high PAR wave but it is visibly bluer.

It is a good idea to get your clam to attach to a small rock incase you need to move it. Maybe you can do this in the future.

 

[crvz]

I'd also recommend more light. Also, not sure if it was asked, but do you have individual reflectors on the T5 bulbs? That may help as well.

 

[khanb31]

well, if there was any clam to pick to put under that amount of lighting.....that was the wrong one. Based off of what you said and the looks of the shell type, youve got a crocea clam. Those croceas (along with the maximas) need the highest intensity of light of all the clams we see in the trade. And from my experiences with clams, (have 3 thus far including a crocea), you have no where near the minimum light requirements for that clam.

On a 75 gallon tank, I would recommend a minimum 2x 150W HQI (double ended) metal halide fixture. But, since your wife is bothered by them, That is out of the option which is ok.

My own personal opinion would be to try doubling or tripling of the higher intensity bulbs. I dont know anything about t5's or VHO's but you gotta get more light on that guy. How about some nice individual reflectors for each bulb? That is a very simple way to increase the light concentration/increase of PAR.

Otherwise, if you cant significantly increase the amount of light over that guy, I would suggest selling him to a local reefer who can or trade it out for a lower light clam. Something like a derasa or squamosa.

As for the removing him from the rock. You must be VERY careful about how you move him. When they attach themselves firmly to a rock, the abysal gland makes attachment strings that goes straight up into their innards and any sharp movement could cause irreparable damage. Try to slowly tilt him left, right, back and forward to see if you can spot where the attachment string is. If your wife is able to help you, have her try and shine a flashlight so you can see better.

When you first start to move the clam, its going to feel you tugging on its gland and will retract everything it can into its shell. After this has happened, you will be able to see a small strand that looks like thinned out floss. You want to cut that strand with a razor blade or a modeling knife/scalpel (preferably - you can keep your dexterity with a scalpel) and then place the clam on something like a frag plug. Here is my crocea and here are the best pictures I could get of the strands.

Put him on a frag plug like this.

With strands outlined.

Without outlines.

Again, with the strands outlined.

Again without the strands outlined.

As you can see there are multiple strands that have attached to the frag plug. Thankfully because of the shape of the plug, the clam can only attach himself to a horizontal base. This makes it easy for me to remove him if I need too. Just because the clam is able to attach himself to something doesnt mean it will keep the clam in place. The strands actually attached to individual pieces of sand in addition to the frag plug....... so it just goes to show you how versatile the strand attachment can be. Im going to put this in the clam forums.....hopefully it will get a sticky. Everyone always wants to know what these things look like.

Any more questions?

 

[khanb31]

I made a post about this in the clam forums. Check it out!

http://reefcentral.com/forums/showthread.php?s=&threadid=1518577

 

[ReefFreek917]

I have 2 ultra blues and both extend the same way. I have 2 400w MH over my 75 and both clams are midway in my tank. I dont think its just a "I need more light" thing. Mine look great and have been in there for almost a year. They just like to extend.



Caleb

 

[Bonneville08]

I don't have a lot of experience with Tridacnas, having only one Crocea under MH lighting, but I was under the impression that the biggest concerns involved bleaching or gaping. If the mantle is well colored completely and the inhalant siphon is not stretched out, you may be OK.
Extra lighting would probably not hurt if the clam is deeper in the tank, but would watch for signs of central bleaching if the intensity is suddenly increased.
This is obviously not the most popular opinion on this thread, but I still consider it valid.

 

[LCDRDATA]

First, thanks to everyone for your continued input.

Second, I've cross-posted this thread on the Tridacnid Clams and other Mollusks forum and had a couple of requests for a top-down shot. Unfortunately I saw those requests AFTER I'd dosed the tank with Liquid Calcium Reactor so the water is somewhat murky and this isn't the best - I'll try and get a better shot tomorrow

I'll admit to being a little conflicted at this point - it's really not clear to me whether light is the issue or not, or even if there is an issue (if ReefFreek917's 800 watts of MH aren't enough to keep one from extending like this, I don't know what would be!). What I have done since I got home from work today is add the 26W 6500K spot I mentioned earlier, and added a pump and flow enhancer to my inlet to significantly increase the overall flow in my tank. Hopefully the photo above - or the one I hope to post tomorrow - will provide a better guide to how this clam is doing. Thanks for the help - please keep it coming!

 

[ducatimikep]

We also have a Croesus clam in our tank.
It is 10" below the surface of 8 - 54w T5's.
It is extended as yours is. He has been there
For 6 months like this with no moving around
So I assume that he is happy. He looks healthy.
So maybe they just like to extend & there really
Isn't a problem? Ours like to extend late in the afternoon,
If that makes a differance.

 

[LCDRDATA]

First of all, here's a much better shot looking straight down -

Second, a respondent on the other thread asked a number of questions; as they are reasonable I'm cross-posting my answers here as well:

how much liquid Ca are you adding???

Generally, I dose KentMarine Liquid Calcium about twice a week per the label directions.

do you add an ALK as well??

Yes; generally, I dose KentMarine ProBuffer dKh about three times a week per the label directions. The product I used last night is a combination calcium and alk source. I also dose magnesium (stock solution mixed from flake) weekly.

how and where and when do you add them??

I measure them out with a graduated cylinder and add them to the sump where the current can mix them a bit more before they hit the intake. The ProBuffer directs to add in the morning, and I generally dose the calcium either a few minutes later or that evening. The product I used last night recommends dosing in the evening, so that's when I dose with it. I'm not using it as often (I'm running out, while I have plenty of the other two products), but I like to use it when I'm changing my flow because it provides a good visual.

the rolling down of the outside edge of the mantle leads me to believe there is and ALK problem but this wouldn't cause the clam to reach.

please post all you test paramaters???

Temp: ~77
Salinity: 1.026
pH: 8.2
Ammonia, Nitrite, Phosphate: 0
Nitrate: 25 (working on it; coming off a spike and down considerably)
Alkalinity: 2.5 meq/l (dKh 7)
Calcium: 470
Magnesium: 1425

the mantle extension isn't the problem, it the fact that it isn't laying down on the shell, it is reaching for light.

can you ask reeffreek to post a pic of his clam??

ReefFreek917, could you do that please?

OK, hopefully that provides enough additional information to help figure this all out.