Gudgeon (Gobio gobio) – freshwater fish belonging to the family Cyprinidae.
The gudgeon is a small fish up to 15 cm long, with a maximum weight of up to 50 grams. The color of the body depends on the environment in which it lives, but is usually grey, yellowish or greenish. There are larger dark freckles along the sideline. Around the mouth there are two moustache-shaped growths.
The gudgeon usually lives in rivers and lakes, especially in winter. In spring and summer, it lives in shallow waters with rocky or sandy bottom or in their vicinity. In late summer and early autumn, it goes into deeper waters with sandy or clayey bottom. In October it retreats and hibernates into lakes or river caves.
The gudgeon is a daytime fish that lies at the bottom during the night, opposing the water stream.
The gudgeon spawns in May and June, when the female lays the sticky eggs on the underwater plants and stones.