I have had more un explained deaths than I feel most... But then I come on these forums or others and see people in the same boat as me. I find it best not to go chasing down stuff, If the whole of the tank is doing well leave it at that. Don't go chasing that one zoa that melted a way. Or that fish that never acclimated right and died within a week. I think of this as more of just a regular everyday hobby... There is a lot of science that goes into it.
I am not I man of many means so it is very discouraging when something you paid good hard earned money for dies, but I feel its all part of the hobby and we learn from our mistakes.
I think the worst in the avoidable issues or the issues caused by yourself. I remember literally almost crying when very expensive beautiful chalice was flipped over in the sand when I came home one day...... I just crossed my fingers flipped her over, and since she has healed very nicely but I remember I really thought I lost it and was very very discouraging.
I have defiantly been threw my ups and downs... just keep with it!