A team of biologists at the University of Padova, in Italy, has found that female zebrafish use their female reproductive fluid (FRF) to choose which sperm to use for fertilizing their eggs. In their study, published in the journal Biology Letters, the group used a specially designed sperm selection tool to collect and test sperm samples.
Click here for original story, Female zebrafish shown to be able to choose which sperm to use to fertilize their eggs
Source: Phys.org