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Let's learn about some strange fish of the mesopelagic, or the twilight zone deep in the ocean! Thanks to Page, Joel, Anonymous Animal Lover, Brigham, and Fireburster for suggestions this week!

Further reading:

In Defense of the Blobfish

Further viewing:

Pacific viperfish (video embedded)

The Pacific viperfish, head-on (or rather teeth-on), still from video linked above:



Sloane's viperfish, rocking those teeth:



The blobfish as it's usually seen on the internet:



The blobfish as it looks when it's cozy in its deep-sea environment:



The barreleye, which I have helpfully labeled for you:



Look at the bristlemouth's sharp thin teeth! Good thing it's only a few inches long:



An indignant bristlemouth (someone should take MS Paint away from me):



The bristlemouth is the most abundant vertebrate in the WORLD (photo by Paul Caiger):



Show transcript:

Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.

Where on earth does the time go? Suddenly we’re halfway through 2021 and I’m still vaguely thinking we’re only a few months in. I’m getting seriously behind on listener suggestions, so let’s have an episode about some weird fish that’s all listener suggestions. Thanks to Page, Joel, an animal lover who wants to remain anonymous, Brigham (whose name I hope I’m pronouncing correctly), and someone who calls themself Fireburster. Fireburster and Anonymous Animal Lover also both left us really nice reviews, so thank you! I picked all these suggestions at random, just grabbing fish suggestions that sounded interesting, but the great thing is they all turned out to live in a specific part of the deep sea.

Brigham and Fireburster both suggested the same fish, so let’s start with that one: the dragon fish. Neither of them specified which kind of dragon fish they’re talking about, though. It’s a popular name for weird fish of various kinds. We’ve even talked about a few before, the Pacific blackdragon of episode 193, which was coincidentally suggested by Page, and the barbeled dragonfish in that same episode. That’s the episode about William Beebe’s mystery fish, which happens to be my current favorite.

We only talked about the barbeled dragonfish briefly before, so let’s learn more about them now.

The barbeled dragonfish gets its name from the filament that hangs down from its chin, called a barbel. If you’ve ever wondered what the proper name for a catfish’s whiskers is, they’re also barbels. The dragonfish’s barbel has a photophore at the end that produces blue-green bioluminescent light, and the fish flashes the light to attract prey. Its head is large and its jaws are full of sharp teeth, so when an animal comes close, CHOMP! The barbeled dragonfish grabs it.

The dragonfish isn’t very big, with the blackdragon that we talked about in episode 193 being the largest at only 16 inches long, or 40 cm. Most species are about half that. So what happens when an animal the same size as or even bigger than the dragonfish happens along?

The dragonfish eats it, that’s what happens. It has large jaws that it can unhinge to swallow prey that’s bigger than it is, and its stomach can expand considerably to hold whatever it swallows. Mostly it just eats tiny animals like krill and amphipods, though.

We don’t know a whole lot about dragonfish. Various species live throughout most of the world’s oceans, especially in tropical and subtropical areas, and they don’t live in the deepest parts of the ocean. Instead, they’re found in what’s called the twilight zone, or more properly the mesopelagic. Only 1% of all light shining down from the surface makes it down this far, which is why so many animals produce their own bioluminescent light. The dragonfish also has photophores along its sides that it can flash to help attract prey or attract mates. On nights when the moon isn’t too bright,