Are bacterial plasmids always conjugative?

No, bacterial plasmids are not always conjugative. Conjugative plasmids carry the genes necessary for their own transfer, including those that encode the conjugation pilus and other machinery. Non-conjugative plasmids lack these genes and cannot initiate transfer on their own. However, they can sometimes be mobilized if a conjugative plasmid is present in the same cell, as it provides the required transfer machinery.