What optical phenomenon do needlefish exploit for launching ambush attacks on prey near the surface?

Answer

Snell's Window

Needlefish utilize Snell's Window, an optical phenomenon caused by light refraction at the water's surface, which distorts images and allows them to launch ballistic ambush attacks.

What optical phenomenon do needlefish exploit for launching ambush attacks on prey near the surface?
animalfishattackfatalityneedlefish