I lost 2 fish a week ago. A Hi-Hat Damsle and a
Fire Goby.
The damsel seemd to have wanderd into the partion side of my tank for the skimmer, this side has a lot turbalent currents and a rock bottom. The bi-color usta-could swim into it, I think the hi-hat seen him do it and attempted it, unfortanly he was to big to swimm back through it. Although the blenni could easly. The Hi-Hat died probly from exustion, then got suck to the gravel ( my intake is under 6 inch of
crushed coral). I didnt find him right away. When I found him I removed him, then I noticed the blennie was acting ill. The ammonia killed him. (.5ppm after a partial water change) He died the next morning from when I found the damsel. He died in the same spot I left him after I inspected him.

... He was my first fish in this tank. After the setup time I buy 1 fish and put him in their to test it, If the fish lives after a week I know it setup just fine. He was 8 months old in my tank.