Throughout much of the world most organism exhibit patriarchal behaviors and similar mating patterns. Even male bacteria and female bacteria show similar roles in conjugation.  Although when observing the behaviors of the Krøyer's deep-sea anglerfish Ceratias holboelli matriarchy is taken to a whole new level and the word stay at home dad is taken to it’s most simplified definition.
First observed in 1922 in an Icelandic fishery by Bjarni Saemundsson when he published a description of two smaller deformed fish attached to the belly of a larger fish. Saemundsson believed the smaller fish to be the young of the larger fish. The fish were both Ceratias holboelli and the small young were the male sexual parasites transforming into a sexual storage appendage for the female.
Both males and females go through a sigmoidal larval stage followed by a metamorphosis where the visually similar males and females grow to become highly specialized and very dissimilar. The male degenerates from a free-living form to become a specialized form ready to parasitize and further devolve. 
The males have less developed olfactory sensory system than their female companions. Therefore males rely solely upon their eyesight to find females, specifically isolate the females light source. Since the male will not need to feed and fend for himself in his parasitic form he exhibits a loss of the proximal mandible with the more distal portion forming into two outward facing sets of spines or barbs called a denticular apparatus. The free-living adult make has only been recorded to reach sizes of 20 mm. The fully developed male then seeks out a female to parasitize. It has been recorded where more than one males have parasitized the same female. After metamorphosis  free living males do not consume food, but instead maintain energy production through stored molecules in their liver.


Once the female is located the male swims over, sure not to be eaten, and bite onto the female. Clamping down tight the male begins to digest and fuse with the female. There is a complete melding of tissues creating a continuous circulatory system between the two; most hypothesize a parallel to the creation and function of a placenta. An endless supply for nutrients to the male by the female until the male cannot support itself and sloughs off, a whole new meaning to “until death do a part.” Although the male relies upon the female for blood, it is only the nutrients the male is after. Attached males still maintain well-developed gills and heart systems.  Also the male liver grows considerably in size once bonded to the female, since this is it’s only source to produce energy from the females blood.
Taking into account that females are under great predatory pressure due to self advertising escal apparatus, difference in lifespan and natural frequency in environment there are roughly 15 to 30 males ready to “mate” per metamorphosed female.
It is hypothesized that the union of male and female is such that the female may perhaps be able to control the seminal vesicles of the male to release sperm at the moment when her eggs are most ripe.
Although this method of reproduction is very peculiar and radical when compared to other forms when taking into account the environment and the lifestyle of the anglerfish it is rather necessary. Anglerfish are far less active than other organisms in their surroundings, mostly letting fish come to them. The female anglerfish does not seek out food, let alone mate. Also taking into account the small number of total anglerfish in such a large pitch-black habitat it is a literal necessity to develop such a technique from such daunting selective environmental and behavioral pressures.

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