Linked from
The 27 pages that link to Caudal fin, each with the reason it gives.
TailBroader topic: In many fishes, the tail’s fin supplies thrust for swimming.
Fish finBroader topic: Its size and shape strongly influence thrust and swimming performance.
Animal finBroader topic: In many fishes, the caudal fin supplies much of the forward thrust.
FilefishBroader topic: Filefish can use the tail for bursts of speed when maneuvering or escaping.
HeterocongrinaeBroader topic: Garden eels use tail movements to dig and secure their burrows.