Ocean Sunfish

The heaviest bony fish, shaped like a swimming head with no tail/Deep Sea & Ocean Life

The ocean sunfish (Mola mola) is the heaviest known bony fish in the world, with some individuals weighing over 2,300 kg. Its bizarre shape resembles a giant head with fins, as it appears to lack a true tail fin. Instead, its dorsal and anal fins extend backward, and a rounded clavus replaces the missing tail. Despite its awkward appearance, it can dive to depths of over 600 meters. Ocean sunfish can grow from a larva of just 2.5 mm to an adult over 3 meters long, an increase of roughly 60 million times in mass. They bask at the surface, prompting seabirds to pick parasites from their skin.