So sorry to hear that! I know how hard it can be to lose a fish. Especially when you are trying everything in your power to care for it.
It is easy to beat ourselves up about it, but just remember it may very well have just been an unhealthy specimen when you got it. I have read that these guys can be tough to get eating and commonly have decompression issues since they are sometimes collected in deep water. It could be any number of things that are out of your control.
I wish you the best with your reef tank in the new year!
