Awesome pic!
I bought a small school of green chromis (6). They stayed together nicely in my tank, then slowly they started dying off, one by one. I would find their dead bodies attached to the intakes of powerheads. Turns out, I watched it happen one day, the smaller ones could not swim away from the intake of one of my powerheads and would get stuck to the filter, eventually dying.
That powerhead has been replaced, but there are only 2 chromis left. I plan on getting more when my 120 is setup.