An important symbol in F451 is the salamander. The salamander is associated historically with fire, particularly with elemental fire.
Here's an excerpt from Wikipedia:
"Of all the traits ascribed to salamanders, the ones relating to fire have stood out most prominently in salamander lore. This connection probably originates from a behavior common to many species of salamander: hibernating in and under rotting logs. When wood was brought indoors and put on the fire, the creatures "mysteriously" appeared from the flames. The 16th-century Italian artist Benvenuto Cellini (1500–1571) famously recalled witnessing just such an appearance as a child in his autobiography.[20]According to some writers, the milky substance that a salamander exudes when frightened and which makes its skin moist gave rise to the idea that the salamander could withstand any heat and even put out fires.[20][21]"