Sexing in tilapia, how its done
Sexing young fish smaller than 100 grams is not easy. Seeing that tilapia are the most popular fish in aquaponic systems worldwide, we will focus on how to sex them visually. If you sex them correctly and create the right environment for the breeding pair, you will soon have a lot of these little guys
Sexing in tilapia is done in two ways, that is, manual hand sexing and hormonal sex reversal.
In hand sexing, sexual features distinguishing males from females are clear when fish is mature, and this occurs at about 10cm.
The males have two orifices; one is the urogenital opening and the other is the anus. Females have three orifices, the genital opening, the anus and the urinary orifice.
Manual sexing should be done early in the morning so that fish is not stressed by high water temperatures.
When breeding tilapia in fish ponds, brood fish is selected and stocked in the ratio of male to female of 1:3.
Fries are harvested from the pond every 15 to 21 days depending on the water temperatures, feeds and water quality aspects.
Under pond conditions, spawning or breeding does not normally occur because the final stimulus associated with a rise in water level and inundation of marginal areas does not happen.
However, they can be induced to spawn by hormonal treatment using pituitary glands from donor fish or synthetic hormones