Author: (Linnaeus, 1758)
FBname: Gudgeon
Comments: Occurs in nearly all types of riverine and lacustrine habitats with sand bottom.  Found in small mountain streams, large lowland rivers and large lakes (Ref. 59043). Inhabits fast flowing rivers with sand or gravel bottom but may also occur in still waters.  Forms schools.  Feeds on insect larvae, mollusks, and crustaceans.  Normally active during the day but if they are disturbed, in particular, by predators, they can defer their activity to periods when light intensity is weak.  Capable of emitting squeaking sounds.  These vocalizations, which is a means by which fish communicate with each other, vary with the degree of activity and the temperature and are independent of the season of reproduction (Ref. 30578).  Breeds in shallow water over stones, sand or plant material.  Eggs are released above substrate and drift with current, sinking to bottom and sticking to substrate. Larvae and juveniles occur on the bottom and prefer detritus-rich sandy habitats and low current (Ref. 59043).