UTTAR PRADESH JOURNAL OF ZOOLOGY

Rainwater-harvesting ponds offer opportunities for freshwater aquaculture by enabling the additional productive use of existing water-storage structures. Nile tilapia (Oreochromis niloticus) is widely cultured because of its adaptability to different freshwater environments. However, evaluating its growth under site-specific pond conditions is essential for understanding its performance and the potential suitability of rainwater-harvesting ponds for fish culture. This study described the weekly growth of Nile tilapia (Oreochromis niloticus) cultured in a rainwater-harvesting aquaculture pond at H.H. The Rajah’s College, Pudukkottai, from September 2023 to February 2024. Fish received commercial feed daily, and average body weight and body length were recorded at weekly intervals over a 24-week culture period. The initial recorded mean weight and length in Week 1 were 3.0 g and 1.5 cm, respectively. By Week 12, mean weight had increased to 110.0 g and mean length to 16.9 cm. At Week 24, the corresponding values reached 550.0 g and 30.2 cm. Across the recorded observations, average body weight increased by 547.0 g and average body length by 28.7 cm. Both measurements increased in every successive weekly record. Weight gains were smaller during the initial weeks and larger in absolute terms during the later stages, whereas increases in length followed a steadier pattern. These results document a continuous rise in mean fish size during one culture cycle in the study pond. However, the absence of a comparison pond, water-quality measurements, fish counts, variability estimates and feed-utilisation data prevents attribution of the growth pattern to the rainwater-harvesting system or assessment of production efficiency. The observations indicate that this pond supported tilapia growth during the monitored period, while further measurements would be required to evaluate broader culture performance.