10- Deep sea hatchet fish
Deep-sea hatchet fishes are small deep-sea mesopelagic ray-finned fish.
Probably the most notorious nightmare animal ever since it terrorised Nemo, some species of male anglerfish mate by biting into a female anglerfish and releasing bacteria that fuse their blood vessels together. All the male’s organs minus the testes slowly degenerate, and he lives the rest of his life as a tumour testicle, feeding off the female’s food intake in exchange for a steady supply of sperm.
12- Black dragonfish
Black Dragonfish are long, slender fish which live in mesopelagic to bathypelagic waters at depths of about 2,000 m. You are not gonna sleep alright after having a peek at the picture.