Torn Byssal Glands on New Clams

[bonebrake]

I purchased two new clams (a T. maxima and a T. crocea) both of which unfortunately have had their byssal glands completely severed from whatever they were previously attached to. This may be worded improperly because as I understand it the byssal glands are internal and it extends byssal threads, but the torn threads were a thick stump - not just a few threads hanging off. Will this torn structure regenerate? Is this fatal? What are the short-term and long-term implications of this?
Note: I've had both clams for five days, they are opening to the light and close when shadowed or physically disturbed. There is no evidence of predatory snails or pinched mantle.
Water parameters:
pH: 8.4
Temperature: 78.0 *F
Salinity: 35 ppt
Ammonia: 0 ppm
Nitrite: 0 ppm
Nitrate: 0 ppm
Calcium: 420 ppm
Alkalinity 3.5 meq/L
Magnesium: 1350 ppm
Phosphorus: 0 ppm
I do weekly 20% water changes.
Current Tank: 90 gal. display with a 100 gal. refugium. Display: Wave2K wavemaker (4000 GPH) and ~300 GPH return pump, (2) 250 watt HQI DE 15,000 K and (4) 65 watt PC actinic 03. Refugium: 100 gal. (2) 300 watt 5500 K halogen lamps on a reverse photo period running 16 hrs. per day.

 

[nietzsche]

its normal if theyre cut away from the clam. theyll secrete them again to attach. everytime i receive a clam theyre usually cut, but really far away from the clam. my crocea lost the threads when i got it but regrew them and attached to a rock. since then most of the clams i have received were the same or at least attached to a small piece of rock
does it look like a big bal with loose threads?

 

[bonebrake]

It looks like a stump made of threads with a width of 20 mm that is cut about 5 mm from the base of the clam.

 

[nietzsche]

so from the base to the end of the small stump its 5mm? that seems really short to what ive gotten. put them on the sand bed and place a small piece of rock under them and theyll usually attach to it over a day or 2 days ( if you want them on the sandbed). you might see them drop the stump, but itll secrete new threads. your clams seem healthy by the description. just watch how they do over the week. your parameters are good. how big are the clams?

 

[yosemite sam]

So there are still threads on the clam? That should mean that the byssal gland is intact, or at least still in the clam. Are the threads actually cut (ie they're all the same length), or do they look like the clam has been ripped off whatever it was attached to? Where did you get the clams from and do you know what were they on before you got them (ie sand bed or rock)? And of course, a picture would really help.

 

[bonebrake]

All threads are the same length, almost as if they were harvested off of a smooth surface with a razor blade. I would prefer my clams in the rocks and it appears the crocea will stay there if no one knocks it over, but my maxima has been knocked from the spot I want him three times, so I am going to leave it on the sandbed for the time being. I purchased them from a local fish store and they were in a one inch sandbed there, but they were only there for three days. The crocea is a little over 3" and the maxima is a little over 4". I would post a picture, but I think the crocea is already beginning to secure himself in the rocks and I don't want to disturb either of them again to take a picture. Thanks for the help!

 

[yosemite sam]

If the threads are all the same length, then someone probably cut the clams off of rocks or whatnot in order to sell them. As long as they were gentle, the clams should be ok. It sounds like they're acting normally, so just keep an eye of them. If they start growing new threads, then they'll likely be ok.

 

[bonebrake]

Good news!

Thanks!