I know there are many threads that deal with this topic but i cant find specific answers. Ill be short and simple. Q1. Can any kind of wood be used? Q2. Can i drill a hole in a trunk to use as a cave? Q3. Will fish hurt themselve over the wood? (dumb question sorry) Q4. Do i have to remove the bark or can i let it be? Q5. Can boiling once work? I will then add it to the aquarium and hold it down with rocks.