I've had this T. squamosa over 10 years and it's grown from roughly 4-5" to about 13". The last month or so it's been randomly extending it's mantle only part way. Mildly worrisome as it historicly is always open full but after a day or two it would be open full again for a few days. Then today I noticed it's shells were mismatched and picked it up and noticed the hinge was mostly missing! Obviously I don't know how old it was when I got it but as it's still shy of the max size for the species I would expect it to live longer. The most recent addition about 10 months ago was a Matted Filefish, Acreichthys tomentosus, which has never been seen to bother the clam or any of the corals in the tank. So my question is how long do T. squamosa's live and is there any sign of aging or has anyone had first hand experience with this damage being caused by the filefish.