Spatial synchrony in biological traits (the Moran effect), triggered by environmental change, constitutes a pivotal ecological process governing species fitness and ecosystem stability. However, movement and growth synchrony, alongside their interrelationship and underlying drivers (intrinsic and extrinsic, e.g., age and environmental variability), remain elusive in freshwater fishes. To address this, we reconstructed lifelong movement and growth histories of an endemic fish Schizothorax nukiangensis in the upper Nu-Salween River by integrating otolith microchemistry (i.e., Mg:Ca, Mn:Ca, Sr:Ca, and Ba:Ca) with increment width analysis from 2011 to 2023, and quantified drivers of their synchronies (within and between traits) using linear mixed-effects models. We found that both movement and growth synchrony decreased significantly with increasing temperature variability but responded divergently to other drivers (e.g., age and elevation). Specifically, movement synchrony declined significantly with all examined variables, with fish age acting as the primary contributor (62.49%), followed by elevation (17.85%), temperature variability (8.25%), and discharge variability (3.92%). Conversely, growth synchrony significantly increased with fish age (11.52%) and significantly decreased with temperature variability (4.47%). The positive effect of discharge variability (56.68%) and the negative effect of elevation (27.34%) primarily drove growth synchrony variation, although their independent linear effects were not statistically significant. Crucially, we identified a distinct threshold effect where increasing elevation and temperature variability shifted the interrelationship between movement and growth synchrony from negative to positive. Our findings demonstrate that environmental gradients dynamically decouple and recouple trait synchrony, providing a mechanistic framework for understanding population resilience and informing conservation strategies under climate change.