Bullhead

Names in dialect: marson, cavedon, magnaron.

Bullhead have a large, broad, slightly concave head, with eyes located at the top, and a wide mouth with thick lips; the body is devoid of scales, brown to grey in colour with irregular markings that provide perfect camouflage; the fins (pectoral fins in particular) are highly developed; they grow to less than 15 cm.
Bullhead live in springs, watercourses and lakes including those at high altitudes, with clear, cold (temperatures below 16°C), well-oxygenated waters, with stony and pebble beds. They generally live near the bottom of lakes and rivers, are territorial and prevalently nocturnal. They feed on benthic invertebrates and sometimes the fry of other fish.
Bullhead reach sexual maturity in their second year. Spawning takes place in spring when the male builds a nest by forming a wide cavity under a stone; once a female has been attracted, she enters the nest and lays a few hundred eggs which attach to the underside of the stone. The male then looks after them until they hatch.
Bullhead are highly sensitive to pollution and are considered a biological indicator of a good quality aquatic environment. Bullhead are also affected by the physical alteration of riverbeds (which eliminates natural shelters) and the introduction of salmonids, which prey on them. Highly appreciated as a food fish, bullhead were illegally fished on an intensive scale until a few decades ago.