The wood I got, was sandblasted so there was no bark on it. If you want to be super safe you could peel the bark off I guess after boiling, then boil again just to be safe. I would think that after boiling the wood the bark would be kinda easy to peel off and may come off in your tank over time. Might just be easier to get it done with and peel it off right away but you could always experiment with some wood in water, just have it sitting in there. one with bark, one without and just test the water to see how the bark is reacting .