tridacna clam

Question
i dont know if you can help me but you seem to have the most experience.
75 gallon tank with 30 gal sump
two clown's
one yellow tang
one blenny,
two orange mandarins one female one male.
four turbo snails, three scarlet crabs, one emerald crab, one porcelain crab, one skunk shrimp, and one queen conk
we also have two yellow leather corals one patch of green polyps two tree corals
we also have a coco worm that we aquired from another reef store who told us it was an easy keeper after diligence and two days the coco worm is out has grown almost a inch of new tube and seems to be very happy
the tank has been up for just over three months. we realize that we put some things in the tank before we should have but have been guided very carefully by a 30 year reefer. I can not get a hold of him so that is why i am turning here.we have 120 pounds of live rock. the tank is a reef with some fish tank.
here is my problem; my husband really wanted a maxima clam so we bought a small one approximately 2-21/2 inches, we acclimated him for almost an hour then placed him in the bottom of the tank in a few minutes he opened up and looked beatiful however about an hour later we noticed our conk sitting on top of him, so i plucked it off the clam and placed it in a diff. spot in tank, i stood there and watched the clam did open back up but did not fully come back out then a few minutes later here comes the conk again, after about four more attempts by the conk to get back to the clam and my moving the conk away from the clam he once again when i walked away from the tank for a few minutes he was on the clam again clam could not totally close as the conk was using his foot in the opening to keep it open and looked as though it was trying to tear the clam apart, i once again removed the conk and placed him in a floating bag on top of my tank. the clam opened back up today but looks like it has a large tear in the bottom opening and did not extend his lips out of shell. why in the world would the conk attack and try to kill the clam, and i am not sure if clam is dead or not it has been 24 hours since this happened and clam still has blue color but also the large tear. please please help me if you can.
thank you for any help you can give

Answer
Hi Lori

It appears that the conch may be trying to consume the clam, whichfrom experience, is not too uncommon.  This is especially true if the following apply:

The clam is new
The clam is small
The clam is stressed
The clam is sick

The first three definitely apply to you, but I would not rule out the fourth.

I had a small maxima clam which was 'healthy' one day and completely eaten the next.

It appears to be fairly common that smaller maxima clams do not do as well in captivity for many reason.

I would suggest that you permanently remove the conch and any others that you have.

If you need any more help, please do not hesitate to contact me again.

Kind Regards,

Michael