freshwater
Common Bleak
Alburnus alburnus
Slender, compressed body with a silvery sheen, bluish-green back, and white belly. It has large, easily detached scales and a distinctly upturned mouth adapted for surface feeding. The fins are translucent to yellowish.
- Habitat
- Inhabits clean, well-oxygenated freshwater rivers, strea…
- Size & weight
- Usually grows to 12-15 cm in length with a weight of aro…
- Diet
- Feeds primarily on zooplankton, surface insects, and dri…
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Physical characteristics
Slender, compressed body with a silvery sheen, bluish-green back, and white belly. It has large, easily detached scales and a distinctly upturned mouth adapted for surface feeding. The fins are translucent to yellowish.
Habitat & distribution
Inhabits clean, well-oxygenated freshwater rivers, streams, and lakes across Europe and parts of Asia, typically preferring slow-flowing sections and open pelagic waters.
Behavior
Highly social, forming large schools in open water near the surface, and is active primarily during daylight hours.
Diet
Feeds primarily on zooplankton, surface insects, and drifting organic matter.
Reproduction
Spawns in shallow, gravelly areas near the margins of lakes or rivers during spring, where females release adhesive eggs onto plants or stones.
Ecological role
Serves as an essential forage fish, forming a critical link in the aquatic food web by transferring energy from plankton to larger piscivorous fish and birds.
Similar species
Similar to other small cyprinids such as minnows and bleak-like species, but distinguished by its strongly upturned mouth, higher lateral line scale count, and very easily shed scales.
Identification tips
Look for the silvery, slender body, deeply forked tail, superior (upturned) mouth, and scales that easily rub off.
Interesting facts
Historically, the reflective scales of the bleak were used in the commercial manufacturing of artificial pearls, known as essence d'orient.