Ocean Sunfish

The ocean sunfish is the heaviest known bony fish in the world, found in temperate and tropical waters across the globe, instantly recognizable by its flattened, near-circular body that appears to end abruptly without a true tail, propelled instead by tall dorsal and anal fins. Adults can weigh well over a tonne, and the species is often seen basking at the ocean surface on its side, a behavior thought to help it warm up after diving into cold water and to allow seabirds to pick parasites from its skin. It feeds mainly on jellyfish and other soft-bodied drifting animals, though it also eats small fish, crustaceans and algae, a diet low in nutrition that requires it to consume very large quantities. Female ocean sunfish are thought to produce more eggs than any other known vertebrate, though only a tiny fraction survive to adulthood. Slow-moving and often struck by boats or entangled in fishing gear, the species is considered vulnerable in parts of its range.