There are a lot of creatures, both big and small, living in the less than five percent of the world's oceans we've explored so far. Occasionally, humans are lucky enough to catch a glimpse of particularly extraordinary specieslike the largest known bony fish in the world. According to the Today Show, a 2013 video captured by diver-photographer Miguel Pereira off the coast of Portugal recently went viral because it provides an up-close look at a massive Mola mola, also known as the Ocean Sunfish.

Mola mola weigh up to 5000 pounds and grow to be 14 feet tall from fin to fin. Even the average adult is a towering predator at 10 feet tall. Despite their size, sunfish are described as being “harmless” and pose no real threat to humans—which is why the divers are able to get so close to this one for photos of its large flat head and fused teeth.

Videos of the large fish have surfaced before, including controversial clips of people riding them like horses. The divers in the video above are much more considerate to the gentle giant, and after a few photos, they send it on its way.

Images via YouTube / Miguel Pereira

[h/t Today]