Powerhead Safety

I had two incidents with my new nano powerhead in the past two days. First I apparently put it too close to the colt coral and it sucked a branch in - luckily it was just a little bit and it was fine. Then, today, I come home to find my new little clown goby had been sucked into it and died. :( The gap for suction was only about the size of a pencil eraser, but apparently that was big enough for disaster.



So, my now I'm looking at all my powerheads as death traps. I recently heard of putting panty hose around them, anyone tried this? Any other tips for fish/coral proofing the powerheads?