sad days

[psuedo]

I have been having such horrible luck with my tank lately. All my parameters are excellent and my lighting is great and I skim. All my corals are doing great and have full extension.
My only problem is that I am having trouble keeping fish right now. My Maroon is doing great and so is my high finned goby. All my inverts are happy as heck. However I have lost 3 tangs in the last month or so, a dottyback, and a wrasse. All the fish were eating right up to their demise and were swimming around.
Can it just be chalked up to bad luck? Maybe I am a bad parent? The food is good as it has all been fresh. What else could it be? Any ideas?