How was the bondage between the old man and the fish?

Santiago had a special connection with the giant Marlin. The old man frequently called the Marlin his brother. His kinship with the Marlin is borne out of the common struggle that they share. Like Santiago once saw himself as majestic (note the lion dreams), the Marlin personifies the same majesty. The idea of predator and prey become blurred. Indeed at one point in during the struggle, Santiago asks the Marlin to kill him. Even after Santiago has killed the Marlin, and is transporting the body strapped to his ship, Santiago curses the sharks who are not worthy to partake from his fiend.