The anglerfish is an iconic creature of the deep ocean, instantly recognizable by the glowing lure that projects from its head. This fishing rod-like appendage, called the illicium, terminates in a fleshy bulb (esca) containing bioluminescent bacteria. This lure attracts unsuspecting prey in the abyss. While famous for this unique predatory strategy, the size of anglerfish compared to a human reveals a surprising range.
The Wide Spectrum of Anglerfish Size
The term “anglerfish” refers to the entire order Lophiiformes, which includes over 350 different species inhabiting various marine environments. Their body sizes vary dramatically, from creatures smaller than a human thumb to massive fish that rival a person in length. Many well-known species belong to the deep-sea suborder Ceratioidei, comprising approximately 200 distinct forms.
These deep-sea dwellers live in the pelagic zone, where scarce food leads to a generally smaller body size. However, the order also includes shallow-water species, such as the frogfish and the goosefish, which exhibit different forms and dimensions. For example, the diminutive male of the deep-sea species Photocorynus spiniceps is one of the smallest known vertebrates, measuring only a few millimeters.
Direct Size Comparison to a Human
When comparing the largest anglerfish to a human, shallow-water species are generally the largest. The European monkfish (Lophius piscatorius), found on continental shelves, can grow up to 2 meters (6.6 feet) long. This maximum size means the monkfish can be longer than the average adult human, though its flattened body shape makes it look less imposing.
In contrast, the largest deep-sea anglerfish, such as the female Krøyer’s deep-sea angler (Ceratias holboelli), typically reach a maximum length of about 1.2 meters (4 feet). This size is considerably smaller than a human, roughly comparable to a small child. Most deep-sea anglerfish specimens encountered by researchers are much smaller, often measuring less than 30 centimeters (1 foot).
The iconic, bulbous deep-sea anglerfish frequently depicted in media, like the female black seadevil (Melanocetus genus), is often only about the size of a softball or a clenched human fist. While a few species can approach or exceed human height, the vast majority of the 350 anglerfish species are significantly smaller than an adult human.
Extreme Size Differences Between Sexes
The size comparison is complicated by the extreme sexual dimorphism found in many deep-sea anglerfish. The large, predatory fish equipped with the bioluminescent lure is always the female. She is self-sufficient, hunting and growing up to four feet long in some species.
The male is drastically different in size and function, often being hundreds of thousands of times lighter than the female. These dwarf males, sometimes only a few centimeters long, lack the large mouth and digestive system needed for independent survival in the resource-scarce deep ocean. The male’s primary purpose is to find a female using his highly developed sense of smell to track her chemical signals.
Once the male locates a female, he bites onto her body, and their tissues and circulatory systems fuse in a process known as sexual parasitism. The male becomes entirely dependent on the female for nourishment, absorbing nutrients directly from her blood supply. This permanent fusion turns the male into a reproductive appendage that provides sperm when the female is ready to spawn. This strategy ensures reproduction in an environment where finding a mate is rare.