Common Thresher Shark

Alopias vulpinus

Maximum length: 5.7 m (~18.7 ft)
Diet: Fishes & squids
Lifespan: ~40 years
Key features: Teal-gray coloration, upper tail lobe nearly the length of their body, long pectoral fins
Fun fact: Common thresher sharks use their tail as a whip to stun fish, but instead of thrashing side-to-side, they launch their tail overhead.

Side view of a common thresher share in clear blue water shows it remarkable long tail extending behind it.

In this video, a thresher shark uses its tail to stun and catch fish. (Source: Discovery Channel )