http://en.wikipedia.org/wiki/Angler_fish#Aspects_of_reproduction
"Aspects of reproduction
Anglerfishes of the suborder Ceratioidea employ an unusual mating method. Since individuals are presumably locally rare and encounters doubly so, finding a mate is problematic. When scientists first started capturing ceratioid anglerfish, they noticed that all of the specimens were females. These individuals were a few inches in size and almost all of them had what appeared to be parasites attached to them. It turned out that these "parasites" were the remains of male ceratioids.
At birth, male ceratioids are already equipped with extremely well developed olfactory organs that detect scents in the water. They have no digestive system, and thus are unable to feed independently. They must find a female anglerfish, and quickly, or else they will die. The sensitive olfactory organs help the male to detect the pheromones that signal the proximity of a female anglerfish. When he finds a female, he bites into her flank, and releases an enzyme which digests the skin of his mouth and her body, fusing the pair down to the blood vessel level. The male then atrophies into nothing more than a pair of gonads that release sperm in response to hormones in the female's bloodstream indicating egg release. This is an extreme example of sexual dimorphism. However, it ensures that when the female is ready to spawn, she has a mate immediately available.[2]
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Originally posted by zeeblebotInteresting, and slightly terrifying.
http://en.wikipedia.org/wiki/Angler_fish#Aspects_of_reproduction
"Aspects of reproduction
Anglerfishes of the suborder Ceratioidea employ an unusual mating method. Since individuals are presumably locally rare and encounters doubly so, finding a mate is problematic. When scientists first started capturing ceratioid anglerfish, they noticed that all o ...[text shortened]... ensures that when the female is ready to spawn, she has a mate immediately available.[2]
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