The Pacific barreleye fish is one the weirdest creatures lurking deep in the ocean. Named after its eyes that are literally shaped like barrels, the species' most unique trait is the completely transparent head.
Koran Angelfish or Pomacanthus semicirculatus belong to the family Pomacanthidae. This species is endemic to the Indo-Pacific and the Rea Sea as far east as Samoa. Their geographical range stretches fromJapan down the entire east coast of Africa to Western Australia and New South Wales. These are marine reef fish, occupying depths from 3-100 feet.
In the deep sea, the only forms of light are bioluminescence and dim sunlight from the surface, most commonly peaking in the blue spectrum. Therefore, most deep-sea species have one photopigment that is sensitive to blue-green light. They found deep-sea shrimps with both secretory and photophore bioluminescence have two photopigments making them sensitive to both blue-green and near-ultraviolent (near-UV) light.