Angler Fish Males Are Parasitic
If there’s any animal that’s made from nightmares, it’s this fish. Angler fish mating rituals are characterized by extreme sexual dimorphism, with females being much larger than males. The female angler fish lures prey with a glowing appendage called an “esca,” while the male, significantly smaller in size, uses his keen senses to find and attach himself to the female. He becomes a permanent parasite, relying on the female for nourishment and reproductive opportunities. The male’s organs degenerate as he fuses with the female, and when she is ready to reproduce, he fertilizes her eggs internally. This remarkable adaptation ensures the survival of their offspring in the deep-sea environment. (Mental Floss).