Bigeye trevally

Photo: Mark Rosenstein · CC BY-NC

Bigeye trevally form dense, swirling schools inside sheltered caverns and at cleaning stations as a predator-avoidance strategy. Their large eyes are adapted for low-light foraging, making cave environments a natural roosting habitat during the day. Schools at Swallows Cave can number in the thousands and create a living wall of silver fish that parts and reforms around divers.