It looks like "Deep Blue" the great white shark has a challenger in the pelagic heavyweight division. This mindbogglingly large ocean sunfish (Mola mola) was encountered by photographer Miguel Pereira off the coast of Portugal.
With the largest specimens reaching 14 feet (4.2 metres) fin-to-fin and weighing over 5,000 pounds (2.26 tonnes), the ocean sunfish is the heaviest known bony fish in the world. A truly cosmopolitan species, the behemoths can be found worldwide, but because they spend their entire lives in the open ocean, encounters like this are few and far between. "It was perhaps the most spectacular moment that I've had in all the diving that I have done," recalls Aleixo.
We have to applaud the divers for (mostly) resisting the urge to touch the fish. Not only is this considered wildlife harassment, but also the scale-less fish are known to host over 40 different parasites. In fact, some of their parasites even have parasites of their own!
A single female sunfish can produce up to 300 million eggs per brood, which lands the species firmly in the Guinness Book of World Records. Upon hatching, the babies look very little like their adult counterparts, but over time, the "clavus" (that large rudder-like appendage you see in the video) forms from the fin rays. Like their cousin the puffer, you'll notice Mola mola don't have teeth. A fused beak helps them break jellies and other small prey items into pieces, which are then minced by claw-like plates in their throats.
Top header image: Miguel Aleixo