Weird fish of the week: Slender snipe eel

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It's time for another trip to the deep for this week's ocean oddity as we take a look at Nemichthys scolopaceus, more commonly known as the Slender snipe eel or Threadfish.

This strange looking fish certainly lives up to its name with a vastly elongated body, (up to 130cm/4ft 3in long) topped by a bulbous head with large eyes typical of many deep sea species.

Its spine is made up of around 750 vertebrae, more than any other animal species currently known on Earth.

The fish's jaws are greatly extended and curve away from each other at their tip meaning that they don't meet when the fish closes them. These slender  jaws are filled with tiny hooked teeth with which the fish are believed to catch their prey by swimming mouth open, ensnaring any passing crustaceans on these toothy snags before swallowing them.

Another bizarre characteristic is that despite their huge body length, their anus is situated near their head, a short distance behind the pectoral fin. What benefit this adaptation, or their extreme length in general gives them is uncertain.

They have no distinct tail fin, instead their body ends in a long filament and they are thought to swim by means of a rippling motion of their extremely long dorsal and anal fins which both have over 300 rays.

Their scientific name is also very descriptive: 'Nemichthys' from the Greek words for thread and fish and 'scolopaceus' alluding to the fishes' long, beak-like jaws which resemble those of wading birds, such as the snipe, (from where it gets its common name) which are from the family Scolopacidae.

Little is known of their breeding, but degenerative changes in both sexes,(particularly the males whose jaws shorten with age) suggest they may be semelparous like many other eel species, dying after breeding.

They are distributed world wide in tropical and temperate seas usually at depths of 400m or below.