Pinkerton (our yellow Goby) survived not one, but two trips into the filter and amazingly survived both, seemingly unfazed by his trips. We found some 1inch white PVC tubing, slit it down the middle and slid it over the back wall, between the tank and the filter chambers. It's just big enough to fit snugly under the lights, thus keeping the fish safely on the right side.
As a side note, I found out while doing this, that clownfish are EXTREMELY territorial and have quite the little attitude when they want too!! After the first few times this insane clownfish tried jumping at us, it then became more aggitated with us messing with the tank, and started flapping water everywhere it could. My face was covered in salt water, shirt was wet, stand was wet, floor and walls wet - all from the fish and it's tantrums!! As I've seen on another post on this message board before - clownfish aren't funny- and this one wanted to rumble!!