The mud-minnow is a small, reddish-brown, irregularly flecked fish with a rounded caudal fin and a lateral line which takes the form of a light stripe along the sides. The head is covered with scales both on the top and sides. It reaches a length of 13 cm at the most and inhabits the basin of the Danube between Vienna and the river's estuary, the lower reaches of the Dniester and Prut, and the lakes Blatenske and Ncziderske. It prefers waters overgrown with vegetation and therefore especially frequents irrigation canals, pools, and old river courses. It usually lives for only two years or so, during which time it feeds on small planktonic crustaceans and benthic organisms. Similar mud-minnows are found in silt- bottomed lakes, pools, and even swamps, in North America.