The biggest fish in the ocean survives on some of the smallest food in it

Whale sharks can grow over 12 metres long, making them the largest fish species alive, yet they feed almost entirely on plankton and small fish, filtering huge volumes of water through their gills as they cruise slowly near the surface. Despite the intimidating size, they're docile enough that divers regularly swim alongside them unharmed.

— First described by Andrew Smith, Whale shark — Rhincodon typus, 1828