Which marine animal is the world's largest fish?

The whale shark is the world's largest fish, despite its common name and enormous size.

Whale sharks are sharks, so they have a cartilaginous skeleton rather than the bony skeleton found in most familiar fish. They are filter feeders that swim with their mouths open, collecting plankton, small fish, fish eggs, and other tiny organisms. Their distinctive checkerboard pattern of pale spots and stripes helps identify individuals.

They live in warm tropical and subtropical waters and often gather where seasonal plankton blooms or fish spawning events provide abundant food. Whale sharks are generally slow-moving and are not considered dangerous to humans, although their size requires respectful distance.

The largest reliably measured individuals exceed 12 metres, while unverified reports have claimed greater lengths. The whale shark is often confused with the basking shark, another large filter-feeding fish, but the whale shark is the larger species and is chiefly associated with warmer seas. Fishing, vessel strikes, and habitat pressures threaten populations.