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MLA Full: "The Rarest Fish in the World is an Anglerfish!" YouTube, uploaded by vlogbrothers, 17 April 2020,
MLA Inline: (vlogbrothers, 2020)
APA Full: vlogbrothers. (2020, April 17). The Rarest Fish in the World is an Anglerfish! [Video]. YouTube.
APA Inline: (vlogbrothers, 2020)
Chicago Full: vlogbrothers, "The Rarest Fish in the World is an Anglerfish!", April 17, 2020, YouTube, 03:59,
To learn more about the amazing work being done to save these fishies, check out

Another thing about handfish that I didn't get into the video is that surveys have shown they don't leave a 10 meter area during any given year of their life. I don't know how they manage to survive this way!

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Good morning, John.  One of the main thing about fish is the swimming.  Being on land can suck because of how stuck you are to it.  Like, the top performing human in the world right now can get like, eight feet off the ground unassisted, and then after all that work, they just come right back down.  This doesn't actually sound that bad until you look at it, but like, lots of animals have like, literally evolved their arms off to be able to swim up into the air.  Bugs, bats, birds, flying is extremely useful.  It adds a third dimension to the two-dimensional world I inhabit.

It's easy to forget that air is a fluid until you stick your face under one of those high-performance hand dryers.  Water is also a fluid.  It's just much more dense.  Animals who live there, all of them fly through water.  

Well, okay, not all of them.  John, this is the red handfish.  They can swim, but they almost never.  Instead, when they move, which they rarely do, they walk across the bottom of the ocean on their modified fins that look almost upsettingly hand-like.  Handfish are a kind of anglerfish and they live in only one place in the world: Southeastern Australia, and they're not doing great.

The red handfish is arguably the rarest fish on Earth.  There are only two population, each with less than 50 adult individuals.  Though it's not for lack of trying.  Handfish moms vigilantly protect their eggs from potential marauders for weeks on end, never leaving them until they hatch, and every time a clutch of red handfish eggs hatches, the world population of red handfish literally doubles.  

So most fish use these hatching events for what's called dispersal.  The little fish are larval forms and they become like, planktonic.  They just let the ocean carry them around.  Most of them end up in places that aren't gonna be great, but some of them end up in places where they can thrive, but no, and this is very weird, handfish babies are just handfish that are smaller.  They have no swim bladders, just like adult handfish.  They just sink to the ground because they are very dense, just like adult handfish.  

So there are these two isolated pockets where red handfish are and all the babies just fall to the ground in the two places where they're left.  This is not great for the survival of the species.  Indeed, and this kind of blew my mind, the IUCN, which is the organization responsible for this stuff, has classified only one marine fish as officially extinct.  That was not meant to be a pun, and this is not to say that there haven't been other marine fish that have gone extinct, this is more a function of not knowing very much about the ocean, but the smooth handfish is known from a single museum specimen that was collected 203 years ago, and after a lot of science and a lot of surveys, it has not been seen since.

Will the red handfish share its fate?  Possibly, but the good news is that the Handfish Conservation Project is right now raising recently hatched handfish in captivity, allowing them to introduce new genetic diversity into these two isolated populations and potentially to reintroduce them to new habitats, and as for why these little anglerfish choose to walk instead of fly through their world, this is really important.  There is a reason, but we do not know it.  We do not know almost everything.  We feel like we do, because we have a tremendous bias toward knowing things that are known because of how we cannot know the things that are unknown.  

Making these bizarre beasts videos reminds me that the things we hear about, these amazing astounding facts from the natural world, every one of those isn't something that somebody, like, picked out of a book.  It was something that was discovered or figured out by a person, but people, the most bizarre of beasts.

John, I'll see you on Tuesday.

Thank you to the wonderful people at the Handfish Conservation Project for helping me out with this video and also for all the lovely footage.  I love your fish!  Thank you for trying to save them.  Check out their work at