Frillish are quite common in Unovan waters, and widely noted for their extreme gender variance in color; the females are pink, the males blue. Their numbers, although never low, increase dramatically after tragedies involving children, so it is generally believed in Unova that a Frillish's body represents a child's soul, which becomes a ghost because it was bitter that it did not get to live a full life on this world. Although there is little in the way of confirmation of this fact, the study of ghost pokemon is still its in infancy, and absent any evidence to the contrary, folk wisdom and the desires of grieving parents have made this speculation widely accepted among Unovans.
As a corollary to this belief, the spirits of male and female children were sought to replicate a Frillish's colors, and each became widely associated first with decorations for infants, but ultimately with an entire gender. That many who die become other ghost pokemon rarely figures into this consideration – few are ever dressed in gold or black for Yamask, for instance, because a Frillish's afterlife is much happier.
In truth, male Frillish are blue to move stealthily through the water, while females use pink to draw others to their brilliance and devour them. Frillish are only halfway dead, and unlike other ghosts still must hunt for food; it is this, not any colors of souls, which accounts for their shade. In truth, the closest things to colors souls have are auras, but these are associated with pokemon type; a pink aura means psychic, not Frillish. The two hunting styles are in fact gendered to ensure that should either method fail, the Frillish pod would migrate elsewhere – perhaps to a healthier sea, or perhaps to the land of the dead.
