Whale shark

The world's largest fish, reaching up to 12 metres, and entirely filter-feeding — no teeth, no threat to divers. Whale sharks congregate at predictable aggregation sites linked to seasonal plankton blooms and coral spawning events. Encounters typically involve slow surface swimming, allowing divers to pace alongside for extended periods. Their spotted pattern is unique to each individual, enabling photo-ID research. Listed as endangered; vessel strikes and fishing bycatch remain significant threats despite international protection.