Malacosteus niger, the Black Dragonfish

The Black Dragonfish

an illuminating presence of the deep

Malacosteus niger is a member of a group of deep water fish known as Dragonfish or Loose-jaws, more commonly known as the Black Dragonfish. This denizen of the deep has stumbled upon an evolutionary cheat code. It has stealth vision.


Most organisms in the deep oceans can only see blue to green light. The reason for this is due to the light absorbing traits of water. By the time any water gets down to where this critter lives (915 to 1,830 m or 3,000 to 6,000 ft), all the red, yellow, orange, and other colors have been absorbed. This is why most bioluminescence is blueish. But the Black Dragonfish is a non-conformist and is not willing to settle with just blue. Instead the Dragonfish relies on a pair of photophores under its eyes that emit red light. With only it and a handful of other species being able to see such wavelengths of light, the Dragonfish can effectively use its photophores as targeting sensors. The red light will shine on its prey and the morsel won’t even know that it has been sighted.

The Black Dragonfish is a major light modifier

To emit red light, the Dragonfish has modified one of its many blue photophores. Using pigments and filters, the light is eventually modified until it is emitted at the proper wavelength of 705 nm, the far red. While this is certainly an interesting adaptation, it is nothing compared to how it actually sees the red light it emits.

Some organisms, such as the closely related genusĀ Aristostomias, just have an extra photoreceptor pigment. But such a simple adaptation that would have been too easy forĀ Malacosteus niger. Instead it makes its own photoreceptor. One of the many things eaten by Dragonfish are copepods. Copepods, in turn, often feed on photosynthetic bacteria. This gives the Dragonfish just the right materials to start fashioning itself spy lenses. Some of the chlorophyll from the bacteria makes its way to the eye where it settles on a photoreceptor. Here, it can absorb the rare red light and transfer the signal to the photoreceptor cells.

This was such a brilliant idea that the idea is now being experimented upon for human use. In experiments involving rabbits and mice, after being given eye-drops with the chlorophyll derivative chlorin e6, the rodents were able to see twice as well in the dark. In time perhaps such an enhancement may be available to people.

black dragonfish niger

Did you like this? Share it:
Posted by on June 12, 2011. Filed under Nature. You can follow any responses to this entry through the RSS 2.0. You can leave a response or trackback to this entry
Back to Main Page

2 Responses to Malacosteus niger, the Black Dragonfish

  1. Cheshire Cat Reply

    June 12, 2011 at 1:50 pm

    I find this creature beautiful in every way and it affirms my long standing belief that Mother Nature is one powerful force. Another great read here today. MM you are really showing off the talent!

  2. Holte Ender Reply

    June 12, 2011 at 4:16 pm

    Not doubt if it was ever available to people the military would snatch it away and classify it.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.