Habitat selection and mobility are major elements of fish population biology. However, little information is available about the behavioral ecology of holobiotic fish in European large rivers. We assessed micro-habitat selection and mobility patterns of two native species of cyprinids (barbel and chub) and of an exotic fish species (catfish) in the heterogeneous hydraulic and thermal conditions (modeled in two-dimensions) of a reach of the large hydropeaking Rhône River, locally warmed by the cooling system of a nuclear power plant. In 2009, we used fixed acoustic telemetry techniques to survey 5 barbels, 7 chubs and 6 catfishes signaling their position every 3-4 s over a three-month period for assessing fish micro-habitat selection in a 2 km-reach. In 2010, we used an active acoustic equipment to track 37 barbels, 23 chubs and 13 catfishes for seven months on a weekly basis for assessing longitudinal home ranges and movements between preferred residence areas in a 35 km-reach. Seven of the individuals tagged in 2009 were also tracked in 2010 and their multi-scale locations enable to better understand their "Fishscape" within the "Riverscape". In the Rhône River, the observations of movements along potential preferential routes suggest that fish can memorize the bathymetry and variations of environmental configurations (hydraulics and temperature) of the reach. At a local scale, fish modify their habitat selection when discharge changes in selecting "least constraining" conditions. At a larger scale they are able to travel rapidly between known habitats.