I don't have expereince with tiger barbs and plecos alongside each other, but I would think that if you kept some tiger barbs in with a bristenose they ought to be fine. The pleco won't be out a ton, so I don't foresee the tiger barbs messing with it too much. However, I'm not sure I'd want to keep tiger barbs in a 29. They are very mobile fish, high-strung almost. Add that to their "picky" attitude, and you may just end up with a mess.