All male fry are treated with testosterone and other hormones to reverse/sterilize females...this is the most common metod in the food production industry.
A less common method is aquiring a "Supermale Tilapia" at about $25K here....
GMT Tilapia A third, less reliable method is crossing a Pure strain Blue Tilapia (O. Aurea) Male with a Pure strain Nile (O. Nilotica) female. Claims of male progeny of up to 95% are often made using this method, but 70% male is more realistic and common.
