Meet the Alien In Deep Sea

Anglerfish is a type of very rare creature living in the deep sea. In most Anglerfish species, there is a long filament protruding out above the fish's eyes, at the tip of the filament there is an irregular growth of flesh (looks like a bulb, called esca). The long filament can move in all directions, while the esca acts as a bait to lure prey to the Anglerfish. When the prey is close enough, the Anglerfish will open its huge jaws and devour the prey whole! The Anglerfish can swallow a prey that is twice its own body size.

In some species of Anglerfish that lives deep under the sea where sunlight is scarce, the esca will emit light due to symbiosis with bacteria. The bacteria enters the esca, starts to multiply rapidly till their collective glow is bright enough to attract other fishes to become the prey of Anglerfish.

Here comes the interesting part, the reproduction of Anglerfish. As Anglerfish is extremely rare, it is very difficult to find a mating partner. In order not to become extinct, the Anglerfish has a very distinct way of reproduction.

At birth, the males are born with well developed olfactory organs (sensory system for smell). When the male Anglerfish mature, its digestive system starts failing, resulting in not able to feed independently. As a result, before the male dies from failure of digestive system, it has to find a female using its powerful olfactory organ. The male can detect pheromones from a mature female using its olfactory organ. So what will happen after the male found his mating partner?

After the male found a female, the male will bite into the female's skin, and digest the skin of his mouth and her body using a type of enzyme secreted. This will enable the couple to fuse with each other to the blood vessel level. The male then degenerates into a pair of gonads that parasites on the female. The gonads (male) release sperm in response to the hormones in the female's bloodstream signalling eggs release. This ensure that, whenever the female is ready to spawn, there will be sperm available to fertilise the eggs.

One of the species of Anglerfish, the little thing protruding

out at the back of the fish is the male that fused with the female

For the Anglerfish, the males reduce to parasites on females after maturation. The males are deemed to sacrifice in the reproduction system in this species, in order to ensure the survival of the species of Anglerfish.