The Danube gudgeon is a small fish with an elongated, spindle-shaped body, which is covered by quite large scales. It has short dorsal and anal fins and a brownish back with dark spots which become purple or.blue at the sides. The mouth is ventral or back behind the head and two long barbels at the sides extend far behind its eyes. The nape is covered with scales. It swims against strong currents and generally lives close to the river bed. It can be encountered in the trout zone and is native to the upper and central parts of the Danube and its tributaries, such as the Isar, and also in rivers of the Carpathian Ukraine and Romania.
Maximum size and weight: 12 cm, 50 g.
Identifying characteristics: Long barbels touch rear gill-cover bones. Nape covered with scales. Purple to blue spots on sides.