So, what’s the world’s biggest fish? That’s easy – it’s the Whale Shark. But what about the world’s longest fish? Well, that’s probably the Whale Shark too, to be honest – the trouble is, it’s a category that tends to attract a lot of over-excited and completely unconfirmable reports. But the other fish that has a claim to be the longest is a species of Oarfish, Regalecus glesne, sometimes called ‘King of Herrings’:
It’s certainly the longest bony fish in the world; i.e. it’s not a shark. As an evolutionary footnote, you are more closely related to the Oarfish than the Oarfish is related to the sharks. If you think about it, that has to be true, because all mammals and bony fish are descended from some first ancestral bony fish, whereas sharks (which have cartilaginous skeletons) are not. The heaviest bony fish is the Sunfish, Mola mola. All giant fish species – the big sharks, the sunfish, and others like the Manta Ray – would be great to see. But the Oarfish really caught my imagination when I learnt about them as a kid, and I’d still love to see one – preferably a big one. How big? Well, they’ve been reliably measured to about 12m (40′), apparently, but reported up to lengths of 17m – 56′. That’s the height of a 5 storey building. Height is the right word here because, as you can see above, they have a very peculiar posture when feeding. Here’s some Navy Seals with a 24′ specimen:
