melanocetids

Melanocetids are a family of deep-sea anglerfish belonging to the order Lophiiformes. These fish are characterized by their extreme sexual dimorphism, with the females being significantly larger and possessing a bioluminescent lure called an esca. This esca is a modified dorsal fin ray that is used to attract prey in the dark depths of the ocean. The males are minuscule by comparison and are parasitic, attaching themselves to the female and fusing their circulatory systems. Their primary function is to provide sperm for reproduction.

The body of a female melanocetid is typically globose and dark in color, often black or deep brown, which aids in camouflage in their aphotic habitat. They have large mouths filled with sharp, inward-pointing teeth, enabling them to ensnare and consume prey that ventures too close to their lure. Melanocetids are found in temperate and tropical oceans worldwide, inhabiting bathyal and abyssal zones at depths ranging from hundreds to thousands of meters. Their diet consists of other fish and invertebrates. The family Melanocetidae contains a single genus, Melanocetus, and several described species. Their unique adaptations make them fascinating examples of evolutionary strategies in extreme environments.