Fish
Bleak
Alburnus alburnus
Just below the surface of a slow river in summer, a shoal of bleak flickers silver in the sunlight, flashing up to snatch a passing fly.
Overview
The bleak, Alburnus alburnus, is a Least Concern carp relative of slow, lowland rivers and lakes across Europe, east to western Asia. Its brilliant scales, surface shoaling, and past use in artificial pearls make it one of the most eye-catching small fish of European waters.
A fish that made pearls
The silvery pigment in bleak scales was once collected and mixed into a lacquer to coat glass beads, giving cheap imitations of real pearls their shine.
Status
Least Concern, widespread and abundant.
Bleak: common questions
What are bleak scales used for?
They contain a silvery pigment, called guanine, which was once extracted to make the shimmering coating of artificial pearls.
How does the bleak feed?
It has an upturned mouth, suited to feeding at the surface, where it snaps up flies and other small insects.
How big is a bleak?
It is usually around 12 to 15 cm long, with a slim, brilliantly silvery body.
Where is the bleak found?
It lives in slow, lowland rivers and lakes across Europe, east to western Asia.