Blueback

Blueback may refer to any of a number of unrelated fish species with blue coloration:
 * Blueback (novel), a 1997 novel by Australian author Tim Winton
 * USS Blueback (SS-326), a US Navy submarine of the Balao-class
 * USS Blueback (SS-581), a Barbel-class submarine and the last non-nuclear submarine to join the US Naval Fleet
 * Beardslee trout or bluebacks
 * Blueback, a juvenile hooded seal
 * Blueback (film), an Australian drama