Anthias need plenty of oxygen
It looks like the reason the Anthias died was suffocation. After talking with a couple of people on Reef Central, it seems reasonable to believe that the large fish in a small amount of water (small bag) would use up oxygen rapidly, and my slow acclimation process was my error. It was recommended to use an airstone while acclimating, even if you are doing so in a bucket of water.
All the water tests were done today.