Why Do Angler Fish Live in Deep Parts of an Ocean?

Protection and Camouflage

• The angler fish's scales are dark in color and able to reflect blue light, which makes it invisible in the depths of the ocean. This adaptation acts as an effective form of protection against predators, as they are unable to see the fish. The angler also uses its camouflage to sneak up on smaller fish, upon which it preys.

Hunting

• The angler relies on the darkness of the deep water to hunt. The fish has developed an elongated dorsal spine, which hangs in front of the fish's head like a fishing rod, hence its name. The tip of the dorsal spine is covered in a bacteria that glows brightly through a process of bioluminescence to attract small fish in the darkness of the deep water. Once the prey is close enough, the angler grabs the fish in its large jaws. The angler's teeth curve toward the inside of its mouth, making escape impossible for captured prey.

Reproduction

• Baby angler fish inhabit shallow waters where they survive by eating plankton. As they develop, they move into the depths. During breeding, the male angler bites the female and, over time, his body merges with hers until he relies on her for sustenance. The male's body then begins to degenerate, losing his eyes and all of his internal organs, besides his testes. It is possible for up to six males to attach themselves to a female at one time. For this reason, the males are far smaller than the female angler fish.

Low Oxygen Levels

• Deep ocean water holds less oxygen due to the high pressure of the environment. The angler fish inhabits deep waters because it only requires a small amount of oxygen to survive. The angler is not designed to move quickly, with small fins and a large body. According to SeaSky.org, the angler fish is known to stay completely still in the water.