Are the angler fish and the viper fish located in the twilight zone?
A. The twilight zone, or in more technical terms, the Mesopelagic zone, is the area of the ocean bordered by the sunlight, or photic zone above, and the darkness below. It’s in this zone where most animals show bioluminescence and very curious features such as large eyes, sharp teeth and expandable jaws and stomachs as a result of the conditions of their deep environment. The viperfish does in fact live in the twilight zone and with its large eyes, sharp teeth and wide jaw, is an example of this kind of deep sea adaptation. Viperfish have a specially adapted hinged skull which is why their jaws can open so wide. They have a long dorsal fin with a lure-like photophore on the end, and have been seen hanging motionless in the water with the lure in front of their mouths waiting for their prey. This way they don’t have to actively hunt, and can conserve precious energy. Although they are often thought of as deep sea fish, they have been found at depths of only 80m, presumable coming up to
