<p>Nonnative fish invasions are a major threat to freshwater biodiversity worldwide. However, drivers of their patterns remain unclear across nonnative species origins (alien vs. translocated) and receiving waterbody types (lotic vs. lentic). Here, we investigated biotic (native assemblage) and abiotic (environmental/anthropogenic) drivers of these patterns in a biodiversity hotspot (Yunnan, China) using fish occurrences across 202 sub-basins. We found that biotic factors explained more variation in nonnative species occurrences than abiotic factors (67–83% vs. 17–33%). At the species origin level, native species richness was the strongest biotic driver for both translocated and alien species invasions, with stronger positive effects on the former. Mean phylogenetic and nearest functional distances to native assemblages were typically the second strongest and negative drivers (except in lentic systems) for alien species, while that for translocated species was the nearest phylogenetic distance. For waterbody type, native species richness contributed more to lotic systems, while mean phylogenetic distance had a stronger effect on alien species in lentic systems. Although abiotic factors generally had weak effects, they explained comparable variation by species origins but more variation in lentic than lotic systems, represented by sub-basin area and discharge variability showing negative associations. Anthropogenic disturbances were positively associated with invasions across origins and waterbody types. Indirect effects of biotic and abiotic factors on nonnative fish invasions were widespread but generally weak. The differing contributions of biotic and abiotic drivers to fish invasions across species origins and waterbody types should be highlighted for informing targeted prevention and management.</p>