Goldfish For Women Only
 

The Prussian Carp, Carassius gibelio, which shares a common ancestor with Goldfish in the recent past exist in populations that have males and females, but others in Poland, Mongolia, and the Baltic Sea are apomicitic and gynogenetic. These populations have only females, who have 3 or 4 sets of chromosomes and use the sperm of other species or their few males to activate their eggs, but not fertilize them. They discard the sperm, and produce only female offspring.