The anglerfish's appearance makes it one of the ocean’s most terrifying creatures, with needlike teeth, huge eyes, a misshapen body, and a hanging light.
Anglerfish are deep fish of the order lophiiformes and live all over the world. Females are known for having an esca, a light attached to a hanging rod made of flesh, which they use for luring prey in.
The light of an esca can be controlled with a muscular flap that covers it occasionally. Its light comes from bioluminescent bacteria that live in a pore. Anglerfish and bacteria have formed a symbiotic relationship that way, with the bacteria aiding the anglerfish in producing light and the anglerfish supplying the bacteria with nutrients. In fact, the bacteria and anglerfish have been collaborating for so long that different species of bacteria are present in different species of anglerfish and the bacteria have evolved to be no longer capable of surviving on their own. Anglerfish have been around for 100 million years, meaning that they were present during the time of the dinosaurs.
Above: an anglerfish from the movie Finding Nemo
Anglerfish are carnivorous and eat shrimp like animals, squids, worms, and lanternfish. An anglerfish can extend its jaw and stomach to fit prey twice its size. It needs to be able to do this because prey is scarce in the deep sea, and it is best to prey on as much as possible when there is an encounter with prey. Anglerfish also have lethargic behavior- they are ambush predators, and this saves energy from hunting in the deep sea, where there is hardly any sunlight and energy is scarce.
One of the most interesting things about anglerfish is how they reproduce. Some species of anglerfish, such as the ceratioid anglerfish, have extreme sexual dimorphism, meaning the anatomy of males and females are very different. Most male anglerfish are smaller than females, however, male ceratioid anglerfish can be up to 60 times smaller than a female. It also has denticles instead of teeth to attach to a female. To reproduce, a male anglerfish will use its strong sense of smell to find a female, and then attach onto it with its denticles.
The female and male then fuse their tissue together and end up sharing a circulatory system. The male ends up becoming a sort of parasite, living off of nutrients and depending on the female for survival. A female ceratioid anglerfish can have multiple male anglerfish attaching onto its body. Eggs are made when the female and male(s) release their eggs and sperm in a synchronized manner using hormones.
Other species of anglerfish do not have such a unique reproduction method; the males are not parasitic. They latch on for a short period of time and release their sperm at the same time the female releases her eggs. The tissues never fuse together.
The current status of anglerfish is not well known. Many sources say they are endangered, but there are also sources that say they were rare to begin with and are not being threatened. Scientists have only been able to see anglerfish face to face in the past two decades, and a lot is still unknown about this mysterious creature of the deep.