What is the extent of the Wels Catfish's native range geographically?

From the Rhine catchment eastward into western Asia

The ancestral distribution of the Wels Catfish demonstrates a broad historical tolerance for varied freshwater conditions across a vast expanse of the Eurasian continent. This significant native range spans from the river systems associated with the Rhine catchment in the west, extending continuously eastward across the continent until it reaches western Asia. The persistence of this single, dominant species across such diverse aquatic geographies—including large lakes and expansive, slow-flowing rivers—indicates a highly successful, stable evolutionary path favoring broad adaptation rather than niche specialization into numerous local forms.