I went through a phase with a loss of fish like that. One small juvy clownfish, and a neon goby. I am pretty sure it was one of the really ugly crabs I pulled out. The disapperance losses stopped.
The only advice would be to set some crab traps
It has been cumalative. My husband kept aggressive tanks before we were together(15 years ago) I have always thought they were beautiful. Snorkeling in Hawaii really was incredible, like swimming in a big fish tank!
What I think drove us back over the edge, and I may be flamed for...