Abstract: As the global population continues to grow and the demand for aquatic products continues to increase, fishery resources in natural waters are under unprecedented pressure. Overfishing has led to a gradual decrease in the variety and quantity of natural fishery resources, and this trend has prompted aquaculture to become an important way to satisfy human demand for aquatic products, and as a high-quality aquatic species, GIFT Oreochromis niloticus, which is widely used worldwide because of its strong reproductive ability, rapid growth, good resistance to adversity, and tender meat, has been widely Cultivation. In-pond raceway system (IPRS), as an emerging aquaculture method, realizes the recycling of aquaculture water through facility-based aquaculture and ecological treatment, which improves the aquaculture efficiency and ecological sustainability. Studies have shown that the pond recirculating raceway aquaculture mode can significantly improve the growth efficiency and meat quality of O. niloticus, but there has not been a clear scientific argument about the appropriate flow rate for Jiffy tilapia under this mode. To determine the appropriate water flow velocity for the cultivation of juvenile GIFT O. niloticus, this experiment investigated the swimming behavior and exercise physiology of GIFT O. niloticus. The experiment employed the "incremental flow velocity method" to measure the swimming speed of juveniles GIFT O. niloticus body length: (3.55±0.47) cm, body weight: (1.63±0.69) g; the tail beat frequency and oxygen consumption rate of GIFT O. niloticus, under different flow speed gradients; and the content of lactate, glycogen, and glucose in the white muscle and liver of juvenile GIFT O. niloticus, under different flow speed gradients and exercise durations. The results showed that the induced speed for juvenile GIFT O. niloticus was (9.76±1.42) cm/s, the critical swimming speed was (75.28±12.30) cm/s, and the burst swimming speed was (57.11±10.80) cm/s; there was a significant linear positive correlation between tail beat frequency and flow speed; the resting oxygen consumption rate was 117.42±38.68 mg/(kg·h), and the oxygen consumption rate increased exponentially with increasing flow speed; the minimum cost of transport occurred at 40% U_crit, and the onset of anaerobic metabolism occurred at 60% U_crit; the proportion of anaerobic metabolic power at the critical swimming speed was 7.87%. Sustained exercise at high flow velocities (≥80% U_crit) for a short duration (20 min) increased fish stress, leading to lactate accumulation; while longer duration (60 min) sustained exercise enhanced fish adaptation to environmental stress, accelerating lactate clearance and utilization; short duration sustained exercise at medium and low flow velocities (≤60% U_crit) accelerated fish recovery. The study indicated that GIFT O. niloticus has strong sustained swimming and hypoxia tolerance capabilities, suggesting that the suitable cultivation flow speed for juvenile GIFT O. niloticus is 32 cm/s, not exceeding 48 cm/s. This research provides technical support for in-pond raceway system cultivation of GIFT O. niloticus.