Common bleak (Alburnus arborella) – small freshwater fish of the carp family (Cyprinidae).
The common bleak has a laterally flattened body, covered with small, easily falling scales. The mouth is terminal and pointed upwards. The dorsal fin begins behind the end of the thoracic fin and ends before the beginning of the anal fin. The tail fin is deeply incised. The thoracic fins are long and almost reach the abdomen.
The upper side of the common bleak’s body is greyish green, while laterally is silvery. The color on the abdomen is milky white. There is a dark thin line along the sides. The average size of the common bleak is 12-15 cm. The maximum size is 20 cm and the weight is up to 50 grams. It matures sexually in the third year of its life at a length of 7-8 cm.
It spawns from May to July, sometimes up to August, in shallow waters. Female fertility ranges from 3000 to 15,000 roe. The roe is sticky and is attached to fine sand, gravel and vegetation. Embryonic development is short and lasts 4-5 days.
The common bleak feeds on plankton and invertebrates, mostly insects.