Yay, another person with a nano. We have a 12g aquapod with 1 blue damsel and 1 ocellaris, and we added the sixline a few months ago. No problems so far. It definitely helped with the bristle worm population, but we do still have some, which I figure is fine. I'm not sure if a sixline is really necessary for your bristle worm pop... sounds like the one you saw was pretty small and I'm assuming skinny, but in my experience, the sixline is a cool fish to watch and it has worked out fine in my tank. HTH!!