For some reason I was in the mood to talk about a bizarre animal today.  As usual, when I am looking for something super extraordinary, I head to the deep depths of the ocean.  What I found down there was the Marine Hatchetfish, which is also known as the Deep Sea Hatchetfish. You can probably tell that this fish gets its name since the shape of their body sort of resembles that of a hatchet.  Don’t worry, I had to look at the picture twice as well to try and make out the hatchet shape.

There are about 45 different species of Hatchetfish ranging in size from 2.5- 15 cm (1-6 inches).  Obviously their most distinctive feature is just how thin their bodies are which gives them the appearance of the blade of a hatchet.  I would like to note right now that it is important not to confuse these deep sea fish with the freshwater hatchetfish that you may have in your aquarium.  They are not the same although, I suppose you could try to put this marine variety into your fish tank.

As with other deep sea fish the Marine Hatchetfish has large, tubular eyes which point up.  Naturally, this allows this dangerous predator to observe its surroundings from the ocean floor.  They have also adapted to the incredibly low light conditions found at these depths.  As a result their eyes are extremely sensitive to light and can make out the slightest shadows amongst the very dim light of the surface.

Of course if they become afraid of the dark then they can always make their own light.  Yep, just like some of the other odd, deep sea creatures the Marine Hatchetfish is capable of creating their own light through bioluminscence.  So what does the Hatchetfish use this light making ability for?  Well, for starters these lights are pointing down towards the ocean floor so it is believed they are largely used to hide themselves from predators.  Believe it or not they will actually adjust the level of light below them to match the surface light, which makes them practically invisible.   As well it is also believed that the lights may also play a role in the mating habits of Marine Hatchetfish but we just don’t know enough yet.  Hey!  There is a potential study for you to get some grant money to carry out.

That does it for another Wild Fact.  So far this week we have gone from the sky to the deepest parts of the sea.  Perhaps tomorrow we will go somewhere in between.  Enjoy the rest of your day!