Habitat: common in deep, temperate and equatorial oceanic waters
Status: Not Listed

Looking at the drawing above, you’re probably thinking it’s from some Hitchhiker’s Guide to the Galaxy… there’s no way that could be an actual creature on Earth… right?

Wrong. This baby (no pun intended) is as real as they come. It’s the larval form of a Black Dragonfish or Ribbon Sawtail Fish (Idiacanthus fasciola), which is found around the world at depths of 500 to 2,000 meters. These fish go through an incredible metamorphosis from larva, postlarva, adolescent, transitional adolescent to adult. Eventually, they end up changing from this:

Idiacanthus fasciola, black dragonfish, larval dragonfish (3)

photo: Carole Baldwin

to this:

Quite a Before-and-After series, eh? Black Dragonfish are also called Deepsea Stalkeye Fish because of their googly-eyed larval state. The larva are long and slender, almost spaghetti like creatures, that grow between 1.6 to 2.8 cm in length, and have amber eyes on very long, cartilaginous stalks that are up to 25% of the total body length. The eyestalks apparently aid it in a wider range of vision (well, we knew it wasn’t for aesthetic purposes…). The head of the larva is flat with a duck-like snout and its intestines extend outside of its body and slightly beyond its caudal fin – you can see it drooping out of the photo above. Attractive.

Once they’re in the adolescent stage, the eyestalks disappear, the intestines get sucked back into the body, the skin darkens, and, in females, rapid growth occurs (they can actually quadruple in length!).  Males don’t grow as much during this stage, but the skin does darken.

Idiacanthus fasciola, black dragonfish, larval dragonfish (5)

Hello Clarice
photo: http://www.elakiri.com/

It really is incredible how something so innocent and sweet looking can morph into a monster later in life. I mean, would you ever think this little dude would become the creature known as a Black DRAGONfish for Pete’s sake?! I would think it would turn into a Yellow HappyWorm or something more along those lines…

So just remember, not everything is always as as its seems in the deep, dark ocean depths…

Idiacanthus fasciola, black dragonfish, larval dragonfish (2)

photo: Michigan Science Art