Problem with Nutrafin Natural Plant System

I got one of the Nutrafin CO2 systems for my 10 gallon. My Pristella Tetras keep getting themselves wedged between the ladder/diffuser and the glass. No casualties yet, but it can't be good to be stuck there for several hours until I notice one is missing. Has anyone else had this problem? Any suggestions?

Thanks, I'll give that a shot. It might be a little unsightly, but that's better than unhappy fish.