I wouldn't. I had both in a 55g and they fell out with one another all the time. The rubberlip sadly died a few weeks ago -- potentially after a dodgy zucchini -- but it might have been stressed as well. I can say with certainty that the bristlenose seems a lot happier being the only pleco in the tank, and I'm not replacing the rubberlip, as much as I liked it. On searching forums, it seems as if people succesfully keep them together without fights, but I wasn't one of them, and you'd definitely need a bigger tank than a 29. 55 was okay in theory, but it might depend on your individual fish.