The max died due to mistreatment.
It was a small unhealthy clam I got at a very cheap price due to it's obvious poor health.
I took a chance, and hoped for the best, but it didn't work out.
It has since been several weeks since the death, and during the wipeout, every clam was dead within 3 weeks of adding a diseased clam. They had started showing symptoms 1 week after the addition of the sick clam.
The clams currently in my tank show no signs of illness. I don't think it is unsafe due to the loss of a small, bleached, and unhappy maxima.