br pPrue Wheeler was out for a morning snorkel along Western Australia’s Ningaloo Reef on May 5 when she saw an extraordinary sight: schools of fish forming a bait balla that then slowly diminished in size.ppA bait ball is created when small fish move tightly packed in a spherical formation around a common center. It is a defensive measure adopted by small schooling fish when they are threatened by predators.pbr pWheeler told Storyful that “these defense maneuvers almost [appeared] choreographed as their silver bodies dazzle in the most incredible formations.