When encountering the picture of the larval form of a the chestburster, alien looking Black Dragonfish or Ribbon Sawtail Fish (Idiacanthus fasciola), you’re probably thinking it’s a science fiction film character. It’s found around the world at depths of 500 to 2,000 meters in temperate and equatorial oceanic waters.
These fish go through an incredible metamorphosis from larva, postlarva, adolescent, transitional adolescent to adult. Eventually, they end up changing from this:
Image: Carole Baldwin
Image: Solvin Zankl Photography
Black Dragonfish are also calledDeepsea 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. 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.
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. Males don’t grow as much during this stage, but the skin does darken.
It really is incredible how something so innocent and sweet looking can morph into a monster later in life: