Credit: Muhammad Shahid Iqbal (Tawakkal)- Pakistan The masculinization of the fry of Nile tilapia (Oreochromis niloticus) –as shown in the photo- is done in 5m2-hapas placed in earthen ponds. In order to judge the age of fry, only fry hatched from collected eggs are used in the sex-reversal process in which the male hormone 17 …