A method for sealing off a section of tubing deep in a well comprises (1) permanently anchoring a tapered anchor in the tubing by lowering a beaded chain ring thereover for wedging the tapered anchor to the tubing at the desired position of sealing off of the tubing, and (2) fixedly attaching a bridge plug to the tubing by actuation of attaching means to the anchor for sealing off the section of tubing at the desired position. Likewise disclosed are a new bridge plug assembly, a new method for fishing for a cylindrical object deep in a well, a new fishing tool, and a new bridge plug element.