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The Telescopefish (Gigantura)

This fish looks like the stuff of nightmares. There are only 2 species in the entire family of Giganturidae, neither of which you would want to see in person. Let's discover more about these odd wonders of nature.

Physical Description and Behavior

These fish are long and slender with large heads and pointed snouts. They also have a long tail that makes up about half of their total body length. Of the two species, Gigantura indica is about 8 in (20 cm) in length, excluding their long tail fin. The other species, Gigantura chuni, is about 6 inches (15.6 cm) in length.

Their mouths are massive and extensile, making up most of the size of their head. In their mouths are thin, sharp teeth that are used to capture prey. While they do not have scales, their body is covered in guanine, which gives them a greenish to purplish iridescence, much like a soap bubble.

Fun fact: These fish are known for their cylindrical tube-shaped eyes. These eyes help them out in the dark mesopelagic to bathypelagic zones 500-3000 m deep. The shape of their eyes increases light collection, allowing them to see bioluminescent prey from farther away. It also allows them to spot prey from above against the backdrop of any light traveling that far deep.

They are believed to be solitary predators. Their prey includes lanternfish, bristlemouths, and barbeled dragonfish. In fact, they often eat their prey whole, including fish bigger than they are. This is not an uncommon trait for fish at these depths.

Habitat and Location

The telescopefish can be found in deep cold tropical waters all over the world. However, due to their thin bodies and the depths at which they live, not many images have been taken of them. Most of the images I have been able to find, outside of the close-ups shown above, are illustrations.

That said, the IUCN Red List lists both of these species as Least Concern. While more information is needed, it is good to know that there are no immediate threats to them.

You can find out more about this genus by checking out the video below:

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