The South-west European nase breeds from March to June (2) (3), with this species moving into smaller tributaries to spawn (3) (6). The eggs are laid in a carefully selected spawning site, which is typically a boulder in a deep pool, downstream of riffles, where the water contains more oxygen and the temperature remains constant (6).
During the larval period, the South-west European nase feeds on plankton, gathering in small shoals at the surface of pools (6). The adult South-west European nase feeds by scraping and ‘pecking’ at algae and small aquatic invertebrates on rocks and pebbles. It will also feed on plants and, occasionally, other small fish (2) (3).