Reproduction takes two… right? This is true for most animal species, with reproduction involving the fusion of a sperm and an egg. However, one fish species has taken a different approach. The Amazon Molly is entirely female. When they are ready to reproduce, members of this species must find a male of another, related species, and mate with him. However, instead of using the sperm from this male to provide half of the genetic information for the future offspring, the female Amazon Molly merely uses the sperm as a signal to trigger embryogenesis, in a process known as gynogenesis.