We took the fish from our stock population (6 fish/l) of Nile
tilapia, O. niloticus L. (1859) that were reared under the following
conditions: indoor tanks, white light (∼300 lux), temperatures
between 24 and 26 ◦C, water saturated with oxygen (DO > 4.0 mg/l),
pH ∼ 7.0, and a photophase from 06:00 h to 18:00 h.