Common Bleak
Alburnus alburnus
Type: freshwater
Physical Characteristics
Slender, elongated, and laterally compressed body. It has a shiny, silvery appearance with a blue-green or grey-green tint on the back. The scales are thin and shed easily. It features a superior mouth (upturned) for surface feeding and a long anal fin with 17-20 rays.
Habitat & Distribution
Occurs in open waters of medium to large rivers and lakes across Europe and Western Asia. It prefers slow-flowing or standing waters and is often found near the surface.
Size & Weight
Standard length is typically 12-15 cm, reaching up to 25 cm. Weight is generally between 10-60 grams, with a maximum recorded weight of around 100 grams.
Similar Looking Species
Common Dace (Leuciscus leuciscus) - has a more rounded body and smaller anal fin; Silver Bream (Blicca bjoerkna) - much deeper body; Common Rudd (Scardinius erythrophthalmus) - has red fins and a deeper body.
Ecological Role
Serves as a vital link in the food chain, converting zooplankton into biomass for larger predatory fish such as Pike, Zander, and Perch, as well as piscivorous birds.
Diet
Mainly an insectivore and planktivore. It feeds on small zooplankton, midges, and flying insects that fall onto the water's surface.
Behavior
A highly gregarious schooling fish that is active during the day. They are often seen jumping from the water to catch insects or to escape predators.
Reproduction
Spawns from May to August in shallow water over stones, gravel, or aquatic vegetation. They are prolific breeders with sticky eggs that adhere to the substrate.
Conservation Status
Least Concern (IUCN). Populations are widespread and generally stable throughout their native range.
Identification Tips
Look for the distinctly upturned mouth, the very bright silvery scales that fall off easily when touched, and the relatively long anal fin.
Interesting Facts
The scales of the Bleak were historically used to manufacture 'Essence d'Orient', a coating for artificial pearls, due to their intense crystalline guanine content.
Identified on: 5/23/2026
Mode: Standard