Effects of CaCO 3 liming on water quality and growth performance of liming on water quality and growth performance of liming on water quality and growth performance of liming on water quality and growth performance of fingerlings of Nile tilapia, fingerlings of Nile tilapia, fingerlings of Nile tilapia, fingerlings of Nile tilapia, Oreochromis niloticus Oreochromis niloticus Oreochromis niloticus Oreochromis niloticus

The present study was carried out for 6 week with Nile tilapia, Oreochomis niloticus , fingerlings (0.77 ± 0.04 g) to assess the effects of moderate CaCO 3 liming on water pH, total alkalinity, calcium hardness, free CO 2 and total ammonia, as well as on fish final body weight, final body length, survival and FCR. Eighteen 25-L polyethylene aquaria were used to hold the experimental fish (15 fish per aquarium). Nine aquaria were set in the lab's indoor room and nine aquaria in its outdoor area. Two types of water (clear or green) and three different water quality managements (none, HCl acidification and CaCO 3 liming) were evaluated simultaneously in a 3 x 2 factorial design. The application of analytical calcium carbonate at 1 g 10 L -1 in the clear or green waters has produced superior Nile tilapia fingerlings' final body weight and length. The best set of limnological conditions that improved Nile tilapia fingerlings growth was the following: pH: 7.4-8.2; total alkalinity > 50 mg L -1 ; calcium hardness > 140 mg L -1 ; free CO 2 0.05).