Tilapia farming involves the culture of the following species:
(i) Oreochromis niloticus
(ii) Oreochromis mossambicus
(iii) Oreochromis aureus
(iv) Oreochromis spilurus
(v) Oreochromis andersonii
(vi) Tilapia zillii.
(vii) Tilapia rendalli
I). Feeding Habits
Tilapias are heterogeneous (i.e. varied) in their feeding. They are hardy (tough, resilient), have rapid growth, and have ability to consume and efficiently assimilate a wide variety of foods.
In natural water bodies, tilapias mature in about two to three years. Under culture they tend to mature early. Sexual features distinguishing males from females are clear when fish mature (about 15 cm in Tilapia zillii and 10 cm in Oreochromis niloticus). Males have pointed papilla while females have flat horizontally slit papilla.
Fecundity refers to the number of eggs produced by a fish in a spawn. This applies well for monocyclic species, that is, once a year breeders. Tilapias are polycyclic (many times breeders) and their ovary may contain eggs at different stages of maturity.
Table 1: Some characteristics that differentiating substrate brooders (Tilapia) and mouth brooders (Oreochromis):
|Egg diameter (mm)||1-1.5||up to 5.0|
|Yolk percentage||less than 25%||up to 45%|
|Yolk colour||pale yellow||Orange|
|Size of fry at feeding||5-6 mm||9-10 mm|
|Courtship||prolonged (monogamous)||brief (polygamous)|
|Longevity (life span)||up to 7 years||over 9 years|