So a very sad coincidence. When i got home YESTERDAY, I went downstairs to see the triggerfish dead on the floor. The same day I mentioned it on this thread. I should have listened months ago when I was told to make a cover for the tank multiple times!^^ Has he ever tried jumping out? First day I bought mine I found it on the floor.. Fortunately he hadn't been there long. I put him back int he tank and he lived. Months later (last week) I found him in the overflow.
Lesson learned.