Cause of poor mantle expansion in T. gigas?

[ReeferAl]

I acquired a gigas clam a few weeks ago. It had been looking fairly normal from the time I got it. It was not expanding its mantle fully but it was expanded over the shell margins. A couple of days age when I got home from work I noted that the mantle expansion had decreased. It still responds rapidly to being touched. At times it almost appears to be gaping slightly, but at other times the siphons look clamped shut. I have noticed it expelling some mucous periodically. Here is a picture of the clam that I took today:

My tank parameters:
Ca 410
alk 3.0 meq
pH ~7.9-8.0 (it rarely gets above 8.2)
nitrate 0.6
phosphate 0.02

lighting:
14KK Phoenix (7- 250 watt bulbs over tank)
VHO actinic supplementation

ppfd on tank bottom at level of clam is about 160 mSm/cm2 (I think I have the units right?)

The flow at the tank bottom is mild to moderate.

I have 2 crocea, 1 maxima and 1 squamosa that are all growing and looking normal.

Any ideas on why it isn't expanding well?

Allen

 

[jay24k]

Any pyramid snails underneath after the lights go off? Could of came with those and hasn't affected your other clams yet. Is the flow heavy where it is? Many times they retract their mantles when the flow is too strong.

 

[ReeferAl]

<a href=showthread.php?s=&postid=8094303#post8094303 target=_blank>Originally posted</a> by jay24k
Any pyramid snails underneath after the lights go off? Could of came with those and hasn't affected your other clams yet. Is the flow heavy where it is? Many times they retract their mantles when the flow is too strong.

I inspected the clam both when I initially got it and last night. No snails. I place the clam in an area where it was somewhat protected from flow and the flow really did not appear to be a problem.

Last evening I read the new RK article by James Fatheree on giant clam diseases. When I got home from work I took another look at the clam. The mantle edges had an appearance of small "pinch pleats" in some areas. I decided it was probably pinched mantle syndrome so I did a freshwater bath (17min). I also scrubbed the inner edge of the shell with a toothbrush. This morning it's still alive so that's a first step. Now I have to keep a close eye on the other clams as well as this one and watch for the disease on the others.

Allen

 

[jay24k]

You should see immediate improvement if it was pinched mantle. This is what I've seen here when people do it. Also, it might take multiple dips as well. Good luck on it.

 

[ReeferAl]

When I brushed the inner surface of the shell some mucousy material came off on the brush. Is that normal clam mucous or could that have been related to protoza from PM? Anyone know?

Allen

 

[ReeferAl]

Well, after 2 days the clam wasn't looking any better. In fact it appeared worse. So I did a second freshwater bath for 30 min. That was 2 days ago. Here is how the clam looks now:

It obviously isn't doing well. (Ignore the small snails on the mantle. I knocked them there by accident just before taking the picture.)

Any ideas? Is there something else going on? Anything else I can try?

Allen

 

[jmaneyapanda]

dude, that things is g-a-p-i-n-g. I dont think it'll come back. good luck.

 

[ReeferAl]

<a href=showthread.php?s=&postid=8139432#post8139432 target=_blank>Originally posted</a> by jmaneyapanda
dude, that things is g-a-p-i-n-g.

I know. I'm still wondering if this was all due to pinched mantle disease or if there was something else going on. It obviously didn't respond well to the freshwater bath. Even after the first bath done after the first picture was taken it looked a little worse rather than better.

I won't give up on it quite yet, but I'm not holding much hope for it.

Allen

 

[OrionN]

Sorry. It look like it is a goner.

 

[-TS-Vash]

Is the LPS in the first pic still close to the clam?

 

[ReeferAl]

<a href=showthread.php?s=&postid=8158426#post8158426 target=_blank>Originally posted</a> by -TS-Vash
Is the LPS in the first pic still close to the clam?

Actually it was 8 or 10 inches away. It is just the view that made it look closer.

Unfortunately, as expected, the clam died yesterday.

Allen

 

[spoonerville]

sorry to hear